BIOGEN INC. has sponsored the creation of one or more 401k plans.
| Measure | Date | Value |
|---|
| 2023 : BIOGEN 401(K) SAVINGS PLAN 2023 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2023-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2023-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2023-12-31 | $0 |
| Total transfer of assets to this plan | 2023-12-31 | $33,680,948 |
| Total transfer of assets from this plan | 2023-12-31 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2023-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2023-12-31 | $0 |
| Expenses. Interest paid | 2023-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2023-12-31 | $0 |
| Total income from all sources (including contributions) | 2023-12-31 | $490,824,534 |
| Total loss/gain on sale of assets | 2023-12-31 | $0 |
| Total of all expenses incurred | 2023-12-31 | $187,673,243 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2023-12-31 | $188,128,836 |
| Expenses. Certain deemed distributions of participant loans | 2023-12-31 | $2,227 |
| Value of total corrective distributions | 2023-12-31 | $289,224 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2023-12-31 | $143,529,507 |
| Value of total assets at end of year | 2023-12-31 | $1,938,085,017 |
| Value of total assets at beginning of year | 2023-12-31 | $1,601,252,778 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2023-12-31 | $-747,044 |
| Total income from rents | 2023-12-31 | $0 |
| Total interest from all sources | 2023-12-31 | $3,661,653 |
| Total dividends received (eg from common stock, registered investment company shares) | 2023-12-31 | $27,757,336 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2023-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2023-12-31 | $27,757,336 |
| Assets. Real estate other than employer real property at end of year | 2023-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2023-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2023-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2023-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2023-12-31 | Yes |
| Value of fidelity bond cover | 2023-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2023-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2023-12-31 | No |
| Contributions received from participants | 2023-12-31 | $79,006,206 |
| Participant contributions at end of year | 2023-12-31 | $11,501,275 |
| Participant contributions at beginning of year | 2023-12-31 | $12,096,505 |
| Participant contributions at end of year | 2023-12-31 | $0 |
| Participant contributions at beginning of year | 2023-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2023-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2023-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2023-12-31 | $12,781,764 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2023-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2023-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2023-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2023-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2023-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2023-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2023-12-31 | $0 |
| Other income not declared elsewhere | 2023-12-31 | $0 |
| Administrative expenses (other) incurred | 2023-12-31 | $0 |
| Liabilities. Value of operating payables at end of year | 2023-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2023-12-31 | $0 |
| Total non interest bearing cash at end of year | 2023-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2023-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2023-12-31 | No |
| Income. Non cash contributions | 2023-12-31 | $0 |
| Value of net income/loss | 2023-12-31 | $303,151,291 |
| Value of net assets at end of year (total assets less liabilities) | 2023-12-31 | $1,938,085,017 |
| Value of net assets at beginning of year (total assets less liabilities) | 2023-12-31 | $1,601,252,778 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2023-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2023-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2023-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2023-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2023-12-31 | $0 |
| Investment advisory and management fees | 2023-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2023-12-31 | $770,053,063 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2023-12-31 | $1,229,803,377 |
| Value of interest in pooled separate accounts at end of year | 2023-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2023-12-31 | $0 |
| Interest on participant loans | 2023-12-31 | $671,160 |
| Income. Interest from loans (other than to participants) | 2023-12-31 | $0 |
| Interest earned on other investments | 2023-12-31 | $0 |
| Income. Interest from US Government securities | 2023-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2023-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2023-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2023-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2023-12-31 | $1,091,445,002 |
| Value of interest in common/collective trusts at beginning of year | 2023-12-31 | $291,860,560 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2023-12-31 | $59,832,798 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2023-12-31 | $61,609,957 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2023-12-31 | $61,609,957 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2023-12-31 | $2,990,493 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2023-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2023-12-31 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at end of year | 2023-12-31 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at beginning of year | 2023-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2023-12-31 | $0 |
| Asset value of US Government securities at end of year | 2023-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2023-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2023-12-31 | $140,781,669 |
| Net investment gain/loss from pooled separate accounts | 2023-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2023-12-31 | $175,094,369 |
| Net gain/loss from 103.12 investment entities | 2023-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2023-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2023-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2023-12-31 | No |
| Assets. Invements in employer securities at end of year | 2023-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2023-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2023-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2023-12-31 | $0 |
| Contributions received in cash from employer | 2023-12-31 | $51,741,537 |
| Employer contributions (assets) at end of year | 2023-12-31 | $5,252,879 |
| Employer contributions (assets) at beginning of year | 2023-12-31 | $5,882,379 |
| Income. Dividends from preferred stock | 2023-12-31 | $0 |
| Income. Dividends from common stock | 2023-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2023-12-31 | $188,128,836 |
| Asset. Corporate debt instrument preferred debt at end of year | 2023-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2023-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2023-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2023-12-31 | $0 |
| Contract administrator fees | 2023-12-31 | $3,900 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2023-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2023-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2023-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2023-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2023-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2023-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2023-12-31 | $0 |
| Did the plan have assets held for investment | 2023-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2023-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2023-12-31 | No |
| Aggregate proceeds on sale of assets | 2023-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2023-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2023-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2023-12-31 | $0 |
| Opinion of an independent qualified public accountant for this plan | 2023-12-31 | Unqualified |
| Accountancy firm name | 2023-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2023-12-31 | 134008324 |
| Unrealized appreciation/depreciation of real estate assets | 2023-01-01 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2023-01-01 | $0 |
| Total unrealized appreciation/depreciation of assets | 2023-01-01 | $0 |
| Total transfer of assets to this plan | 2023-01-01 | $33,680,948 |
| Total transfer of assets from this plan | 2023-01-01 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2023-01-01 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2023-01-01 | $0 |
| Total income from all sources (including contributions) | 2023-01-01 | $490,824,534 |
| Total loss/gain on sale of assets | 2023-01-01 | $0 |
| Total of all expenses incurred | 2023-01-01 | $187,673,243 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2023-01-01 | $188,128,836 |
| Expenses. Certain deemed distributions of participant loans | 2023-01-01 | $2,227 |
| Value of total corrective distributions | 2023-01-01 | $289,224 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2023-01-01 | $143,529,507 |
| Value of total assets at end of year | 2023-01-01 | $1,938,085,017 |
| Value of total assets at beginning of year | 2023-01-01 | $1,601,252,778 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2023-01-01 | $-747,044 |
| Total income from rents | 2023-01-01 | $0 |
| Total interest from all sources | 2023-01-01 | $3,661,653 |
| Total dividends received (eg from common stock, registered investment company shares) | 2023-01-01 | $27,757,336 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2023-01-01 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2023-01-01 | $27,757,336 |
| Assets. Real estate other than employer real property at end of year | 2023-01-01 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2023-01-01 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2023-01-01 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2023-01-01 | $0 |
| Was this plan covered by a fidelity bond | 2023-01-01 | Yes |
| Value of fidelity bond cover | 2023-01-01 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2023-01-01 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2023-01-01 | No |
| Contributions received from participants | 2023-01-01 | $79,006,206 |
| Participant contributions at end of year | 2023-01-01 | $11,501,275 |
| Participant contributions at beginning of year | 2023-01-01 | $12,096,505 |
| Participant contributions at end of year | 2023-01-01 | $0 |
| Participant contributions at beginning of year | 2023-01-01 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2023-01-01 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2023-01-01 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2023-01-01 | $12,781,764 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2023-01-01 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2023-01-01 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2023-01-01 | $0 |
| Assets. Loans (other than to participants) at end of year | 2023-01-01 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2023-01-01 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2023-01-01 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2023-01-01 | $0 |
| Other income not declared elsewhere | 2023-01-01 | $0 |
| Administrative expenses (other) incurred | 2023-01-01 | $0 |
| Liabilities. Value of operating payables at end of year | 2023-01-01 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2023-01-01 | $0 |
| Total non interest bearing cash at end of year | 2023-01-01 | $0 |
| Total non interest bearing cash at beginning of year | 2023-01-01 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2023-01-01 | No |
| Income. Non cash contributions | 2023-01-01 | $0 |
| Value of net income/loss | 2023-01-01 | $303,151,291 |
| Value of net assets at end of year (total assets less liabilities) | 2023-01-01 | $1,938,085,017 |
| Value of net assets at beginning of year (total assets less liabilities) | 2023-01-01 | $1,601,252,778 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2023-01-01 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2023-01-01 | No |
| Were any leases to which the plan was party in default or uncollectible | 2023-01-01 | No |
| Assets. partnership/joint venture interests at end of year | 2023-01-01 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2023-01-01 | $0 |
| Investment advisory and management fees | 2023-01-01 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2023-01-01 | $770,053,063 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2023-01-01 | $1,229,803,377 |
| Value of interest in pooled separate accounts at end of year | 2023-01-01 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2023-01-01 | $0 |
| Interest on participant loans | 2023-01-01 | $671,160 |
| Income. Interest from loans (other than to participants) | 2023-01-01 | $0 |
| Interest earned on other investments | 2023-01-01 | $0 |
| Income. Interest from US Government securities | 2023-01-01 | $0 |
| Income. Interest from corporate debt instruments | 2023-01-01 | $0 |
| Value of interest in master investment trust accounts at end of year | 2023-01-01 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2023-01-01 | $0 |
| Value of interest in common/collective trusts at end of year | 2023-01-01 | $1,091,445,002 |
| Value of interest in common/collective trusts at beginning of year | 2023-01-01 | $291,860,560 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2023-01-01 | $59,832,798 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2023-01-01 | $2,990,493 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2023-01-01 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2023-01-01 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at end of year | 2023-01-01 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at beginning of year | 2023-01-01 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2023-01-01 | $0 |
| Asset value of US Government securities at end of year | 2023-01-01 | $0 |
| Asset value of US Government securities at beginning of year | 2023-01-01 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2023-01-01 | $140,781,669 |
| Net investment gain/loss from pooled separate accounts | 2023-01-01 | $0 |
| Net investment gain or loss from common/collective trusts | 2023-01-01 | $175,094,369 |
| Net gain/loss from 103.12 investment entities | 2023-01-01 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2023-01-01 | No |
| Was there a failure to transmit to the plan any participant contributions | 2023-01-01 | No |
| Has the plan failed to provide any benefit when due under the plan | 2023-01-01 | No |
| Assets. Invements in employer securities at end of year | 2023-01-01 | $0 |
| Assets. Invements in employer securities at beginning of year | 2023-01-01 | $0 |
| Assets. Value of employer real property at end of year | 2023-01-01 | $0 |
| Assets. Value of employer real property at beginning of year | 2023-01-01 | $0 |
| Contributions received in cash from employer | 2023-01-01 | $51,741,537 |
| Employer contributions (assets) at end of year | 2023-01-01 | $5,252,879 |
| Employer contributions (assets) at beginning of year | 2023-01-01 | $5,882,379 |
| Income. Dividends from preferred stock | 2023-01-01 | $0 |
| Income. Dividends from common stock | 2023-01-01 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2023-01-01 | $188,128,836 |
| Asset. Corporate debt instrument preferred debt at end of year | 2023-01-01 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2023-01-01 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2023-01-01 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2023-01-01 | $0 |
| Contract administrator fees | 2023-01-01 | $3,900 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2023-01-01 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2023-01-01 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2023-01-01 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2023-01-01 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2023-01-01 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2023-01-01 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2023-01-01 | $0 |
| Did the plan have assets held for investment | 2023-01-01 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2023-01-01 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2023-01-01 | No |
| Aggregate proceeds on sale of assets | 2023-01-01 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2023-01-01 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2023-01-01 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2023-01-01 | $0 |
| Opinion of an independent qualified public accountant for this plan | 2023-01-01 | 1 |
| Accountancy firm name | 2023-01-01 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2023-01-01 | 134008324 |
| 2022 : BIOGEN 401(K) SAVINGS PLAN 2022 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2022-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2022-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2022-12-31 | $0 |
| Total transfer of assets to this plan | 2022-12-31 | $0 |
| Total transfer of assets from this plan | 2022-12-31 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2022-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2022-12-31 | $0 |
| Expenses. Interest paid | 2022-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2022-12-31 | $0 |
| Total income from all sources (including contributions) | 2022-12-31 | $-239,562,110 |
| Total loss/gain on sale of assets | 2022-12-31 | $0 |
| Total of all expenses incurred | 2022-12-31 | $168,283,305 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2022-12-31 | $169,442,908 |
| Expenses. Certain deemed distributions of participant loans | 2022-12-31 | $0 |
| Value of total corrective distributions | 2022-12-31 | $271,183 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2022-12-31 | $150,133,669 |
| Value of total assets at end of year | 2022-12-31 | $1,601,252,778 |
| Value of total assets at beginning of year | 2022-12-31 | $2,009,098,193 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2022-12-31 | $-1,430,786 |
| Total income from rents | 2022-12-31 | $0 |
| Total interest from all sources | 2022-12-31 | $1,560,728 |
| Total dividends received (eg from common stock, registered investment company shares) | 2022-12-31 | $84,552,241 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2022-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2022-12-31 | $84,552,241 |
| Assets. Real estate other than employer real property at end of year | 2022-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2022-12-31 | $0 |
| Administrative expenses professional fees incurred | 2022-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2022-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2022-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2022-12-31 | Yes |
| Value of fidelity bond cover | 2022-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2022-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2022-12-31 | No |
| Contributions received from participants | 2022-12-31 | $78,427,279 |
| Participant contributions at end of year | 2022-12-31 | $12,096,505 |
| Participant contributions at beginning of year | 2022-12-31 | $12,635,596 |
| Participant contributions at end of year | 2022-12-31 | $0 |
| Participant contributions at beginning of year | 2022-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2022-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2022-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2022-12-31 | $18,764,033 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2022-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2022-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2022-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2022-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2022-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2022-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2022-12-31 | $0 |
| Other income not declared elsewhere | 2022-12-31 | $0 |
| Administrative expenses (other) incurred | 2022-12-31 | $-1,430,786 |
| Liabilities. Value of operating payables at end of year | 2022-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2022-12-31 | $0 |
| Total non interest bearing cash at end of year | 2022-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2022-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2022-12-31 | No |
| Income. Non cash contributions | 2022-12-31 | $0 |
| Value of net income/loss | 2022-12-31 | $-407,845,415 |
| Value of net assets at end of year (total assets less liabilities) | 2022-12-31 | $1,601,252,778 |
| Value of net assets at beginning of year (total assets less liabilities) | 2022-12-31 | $2,009,098,193 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2022-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2022-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2022-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2022-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2022-12-31 | $0 |
| Investment advisory and management fees | 2022-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2022-12-31 | $1,229,803,377 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2022-12-31 | $1,518,752,156 |
| Value of interest in pooled separate accounts at end of year | 2022-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2022-12-31 | $0 |
| Interest on participant loans | 2022-12-31 | $582,589 |
| Income. Interest from loans (other than to participants) | 2022-12-31 | $0 |
| Interest earned on other investments | 2022-12-31 | $0 |
| Income. Interest from US Government securities | 2022-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2022-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2022-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2022-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2022-12-31 | $291,860,560 |
| Value of interest in common/collective trusts at beginning of year | 2022-12-31 | $413,668,881 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2022-12-31 | $61,609,957 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2022-12-31 | $57,971,962 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2022-12-31 | $57,971,962 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2022-12-31 | $978,139 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2022-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2022-12-31 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at end of year | 2022-12-31 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at beginning of year | 2022-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2022-12-31 | $0 |
| Asset value of US Government securities at end of year | 2022-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2022-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2022-12-31 | $-363,087,813 |
| Net investment gain/loss from pooled separate accounts | 2022-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2022-12-31 | $-112,720,935 |
| Net gain/loss from 103.12 investment entities | 2022-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2022-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2022-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2022-12-31 | No |
| Assets. Invements in employer securities at end of year | 2022-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2022-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2022-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2022-12-31 | $0 |
| Contributions received in cash from employer | 2022-12-31 | $52,942,357 |
| Employer contributions (assets) at end of year | 2022-12-31 | $5,882,379 |
| Employer contributions (assets) at beginning of year | 2022-12-31 | $6,069,598 |
| Income. Dividends from preferred stock | 2022-12-31 | $0 |
| Income. Dividends from common stock | 2022-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2022-12-31 | $169,442,908 |
| Asset. Corporate debt instrument preferred debt at end of year | 2022-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2022-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2022-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2022-12-31 | $0 |
| Contract administrator fees | 2022-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2022-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2022-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2022-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2022-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2022-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2022-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2022-12-31 | $0 |
| Did the plan have assets held for investment | 2022-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2022-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2022-12-31 | No |
| Aggregate proceeds on sale of assets | 2022-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2022-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2022-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2022-12-31 | $0 |
| Opinion of an independent qualified public accountant for this plan | 2022-12-31 | Unqualified |
| Accountancy firm name | 2022-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2022-12-31 | 134008324 |
| Unrealized appreciation/depreciation of real estate assets | 2022-01-01 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2022-01-01 | $0 |
| Total unrealized appreciation/depreciation of assets | 2022-01-01 | $0 |
| Total transfer of assets to this plan | 2022-01-01 | $0 |
| Total transfer of assets from this plan | 2022-01-01 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2022-01-01 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2022-01-01 | $0 |
| Total income from all sources (including contributions) | 2022-01-01 | $-239,562,110 |
| Total loss/gain on sale of assets | 2022-01-01 | $0 |
| Total of all expenses incurred | 2022-01-01 | $168,283,305 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2022-01-01 | $169,442,908 |
| Expenses. Certain deemed distributions of participant loans | 2022-01-01 | $0 |
| Value of total corrective distributions | 2022-01-01 | $271,183 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2022-01-01 | $150,133,669 |
| Value of total assets at end of year | 2022-01-01 | $1,601,252,778 |
| Value of total assets at beginning of year | 2022-01-01 | $2,009,098,193 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2022-01-01 | $-1,430,786 |
| Total income from rents | 2022-01-01 | $0 |
| Total interest from all sources | 2022-01-01 | $1,560,728 |
| Total dividends received (eg from common stock, registered investment company shares) | 2022-01-01 | $84,552,241 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2022-01-01 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2022-01-01 | $84,552,241 |
| Assets. Real estate other than employer real property at end of year | 2022-01-01 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2022-01-01 | $0 |
| Administrative expenses professional fees incurred | 2022-01-01 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2022-01-01 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2022-01-01 | $0 |
| Was this plan covered by a fidelity bond | 2022-01-01 | Yes |
| Value of fidelity bond cover | 2022-01-01 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2022-01-01 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2022-01-01 | No |
| Contributions received from participants | 2022-01-01 | $78,427,279 |
| Participant contributions at end of year | 2022-01-01 | $12,096,505 |
| Participant contributions at beginning of year | 2022-01-01 | $12,635,596 |
| Participant contributions at end of year | 2022-01-01 | $0 |
| Participant contributions at beginning of year | 2022-01-01 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2022-01-01 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2022-01-01 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2022-01-01 | $18,764,033 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2022-01-01 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2022-01-01 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2022-01-01 | $0 |
| Assets. Loans (other than to participants) at end of year | 2022-01-01 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2022-01-01 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2022-01-01 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2022-01-01 | $0 |
| Other income not declared elsewhere | 2022-01-01 | $0 |
| Administrative expenses (other) incurred | 2022-01-01 | $-1,430,786 |
| Liabilities. Value of operating payables at end of year | 2022-01-01 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2022-01-01 | $0 |
| Total non interest bearing cash at end of year | 2022-01-01 | $0 |
| Total non interest bearing cash at beginning of year | 2022-01-01 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2022-01-01 | No |
| Income. Non cash contributions | 2022-01-01 | $0 |
| Value of net income/loss | 2022-01-01 | $-407,845,415 |
| Value of net assets at end of year (total assets less liabilities) | 2022-01-01 | $1,601,252,778 |
| Value of net assets at beginning of year (total assets less liabilities) | 2022-01-01 | $2,009,098,193 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2022-01-01 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2022-01-01 | No |
| Were any leases to which the plan was party in default or uncollectible | 2022-01-01 | No |
| Assets. partnership/joint venture interests at end of year | 2022-01-01 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2022-01-01 | $0 |
| Investment advisory and management fees | 2022-01-01 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2022-01-01 | $1,229,803,377 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2022-01-01 | $1,518,752,156 |
| Value of interest in pooled separate accounts at end of year | 2022-01-01 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2022-01-01 | $0 |
| Interest on participant loans | 2022-01-01 | $582,589 |
| Income. Interest from loans (other than to participants) | 2022-01-01 | $0 |
| Interest earned on other investments | 2022-01-01 | $0 |
| Income. Interest from US Government securities | 2022-01-01 | $0 |
| Income. Interest from corporate debt instruments | 2022-01-01 | $0 |
| Value of interest in master investment trust accounts at end of year | 2022-01-01 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2022-01-01 | $0 |
| Value of interest in common/collective trusts at end of year | 2022-01-01 | $291,860,560 |
| Value of interest in common/collective trusts at beginning of year | 2022-01-01 | $413,668,881 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2022-01-01 | $61,609,957 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2022-01-01 | $978,139 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2022-01-01 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2022-01-01 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at end of year | 2022-01-01 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at beginning of year | 2022-01-01 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2022-01-01 | $0 |
| Asset value of US Government securities at end of year | 2022-01-01 | $0 |
| Asset value of US Government securities at beginning of year | 2022-01-01 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2022-01-01 | $-363,087,813 |
| Net investment gain/loss from pooled separate accounts | 2022-01-01 | $0 |
| Net investment gain or loss from common/collective trusts | 2022-01-01 | $-112,720,935 |
| Net gain/loss from 103.12 investment entities | 2022-01-01 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2022-01-01 | No |
| Was there a failure to transmit to the plan any participant contributions | 2022-01-01 | No |
| Has the plan failed to provide any benefit when due under the plan | 2022-01-01 | No |
| Assets. Invements in employer securities at end of year | 2022-01-01 | $0 |
| Assets. Invements in employer securities at beginning of year | 2022-01-01 | $0 |
| Assets. Value of employer real property at end of year | 2022-01-01 | $0 |
| Assets. Value of employer real property at beginning of year | 2022-01-01 | $0 |
| Contributions received in cash from employer | 2022-01-01 | $52,942,357 |
| Employer contributions (assets) at end of year | 2022-01-01 | $5,882,379 |
| Employer contributions (assets) at beginning of year | 2022-01-01 | $6,069,598 |
| Income. Dividends from preferred stock | 2022-01-01 | $0 |
| Income. Dividends from common stock | 2022-01-01 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2022-01-01 | $169,442,908 |
| Asset. Corporate debt instrument preferred debt at end of year | 2022-01-01 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2022-01-01 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2022-01-01 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2022-01-01 | $0 |
| Contract administrator fees | 2022-01-01 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2022-01-01 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2022-01-01 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2022-01-01 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2022-01-01 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2022-01-01 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2022-01-01 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2022-01-01 | $0 |
| Did the plan have assets held for investment | 2022-01-01 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2022-01-01 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2022-01-01 | No |
| Aggregate proceeds on sale of assets | 2022-01-01 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2022-01-01 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2022-01-01 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2022-01-01 | $0 |
| Opinion of an independent qualified public accountant for this plan | 2022-01-01 | 1 |
| Accountancy firm name | 2022-01-01 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2022-01-01 | 134008324 |
| 2021 : BIOGEN 401(K) SAVINGS PLAN 2021 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2021-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2021-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2021-12-31 | $0 |
| Total transfer of assets to this plan | 2021-12-31 | $0 |
| Total transfer of assets from this plan | 2021-12-31 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2021-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2021-12-31 | $0 |
| Expenses. Interest paid | 2021-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2021-12-31 | $0 |
| Total income from all sources (including contributions) | 2021-12-31 | $441,902,036 |
| Total loss/gain on sale of assets | 2021-12-31 | $0 |
| Total of all expenses incurred | 2021-12-31 | $135,491,888 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2021-12-31 | $136,444,115 |
| Expenses. Certain deemed distributions of participant loans | 2021-12-31 | $15,751 |
| Value of total corrective distributions | 2021-12-31 | $280,071 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2021-12-31 | $160,025,878 |
| Value of total assets at end of year | 2021-12-31 | $2,009,098,193 |
| Value of total assets at beginning of year | 2021-12-31 | $1,702,688,045 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2021-12-31 | $-1,248,049 |
| Total income from rents | 2021-12-31 | $0 |
| Total interest from all sources | 2021-12-31 | $594,166 |
| Total dividends received (eg from common stock, registered investment company shares) | 2021-12-31 | $135,270,231 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2021-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2021-12-31 | $135,270,231 |
| Assets. Real estate other than employer real property at end of year | 2021-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2021-12-31 | $0 |
| Administrative expenses professional fees incurred | 2021-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2021-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2021-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2021-12-31 | Yes |
| Value of fidelity bond cover | 2021-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2021-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2021-12-31 | No |
| Contributions received from participants | 2021-12-31 | $80,152,447 |
| Participant contributions at end of year | 2021-12-31 | $12,635,596 |
| Participant contributions at beginning of year | 2021-12-31 | $11,023,896 |
| Participant contributions at end of year | 2021-12-31 | $0 |
| Participant contributions at beginning of year | 2021-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2021-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2021-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2021-12-31 | $25,060,751 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2021-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2021-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2021-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2021-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2021-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2021-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2021-12-31 | $0 |
| Other income not declared elsewhere | 2021-12-31 | $0 |
| Administrative expenses (other) incurred | 2021-12-31 | $-1,248,049 |
| Liabilities. Value of operating payables at end of year | 2021-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2021-12-31 | $0 |
| Total non interest bearing cash at end of year | 2021-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2021-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2021-12-31 | No |
| Income. Non cash contributions | 2021-12-31 | $0 |
| Value of net income/loss | 2021-12-31 | $306,410,148 |
| Value of net assets at end of year (total assets less liabilities) | 2021-12-31 | $2,009,098,193 |
| Value of net assets at beginning of year (total assets less liabilities) | 2021-12-31 | $1,702,688,045 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2021-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2021-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2021-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2021-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2021-12-31 | $0 |
| Investment advisory and management fees | 2021-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2021-12-31 | $1,518,752,156 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2021-12-31 | $1,275,308,491 |
| Value of interest in pooled separate accounts at end of year | 2021-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2021-12-31 | $0 |
| Interest on participant loans | 2021-12-31 | $588,045 |
| Income. Interest from loans (other than to participants) | 2021-12-31 | $0 |
| Interest earned on other investments | 2021-12-31 | $0 |
| Income. Interest from US Government securities | 2021-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2021-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2021-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2021-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2021-12-31 | $413,668,881 |
| Value of interest in common/collective trusts at beginning of year | 2021-12-31 | $350,361,588 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2021-12-31 | $57,971,962 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2021-12-31 | $60,512,257 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2021-12-31 | $60,512,257 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2021-12-31 | $6,121 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2021-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2021-12-31 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at end of year | 2021-12-31 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at beginning of year | 2021-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2021-12-31 | $0 |
| Asset value of US Government securities at end of year | 2021-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2021-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2021-12-31 | $70,379,977 |
| Net investment gain/loss from pooled separate accounts | 2021-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2021-12-31 | $75,631,784 |
| Net gain/loss from 103.12 investment entities | 2021-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2021-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2021-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2021-12-31 | No |
| Assets. Invements in employer securities at end of year | 2021-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2021-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2021-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2021-12-31 | $0 |
| Contributions received in cash from employer | 2021-12-31 | $54,812,680 |
| Employer contributions (assets) at end of year | 2021-12-31 | $6,069,598 |
| Employer contributions (assets) at beginning of year | 2021-12-31 | $5,481,813 |
| Income. Dividends from preferred stock | 2021-12-31 | $0 |
| Income. Dividends from common stock | 2021-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2021-12-31 | $136,444,115 |
| Asset. Corporate debt instrument preferred debt at end of year | 2021-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2021-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2021-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2021-12-31 | $0 |
| Contract administrator fees | 2021-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2021-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2021-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2021-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2021-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2021-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2021-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2021-12-31 | $0 |
| Did the plan have assets held for investment | 2021-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2021-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2021-12-31 | No |
| Aggregate proceeds on sale of assets | 2021-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2021-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2021-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2021-12-31 | $0 |
| Opinion of an independent qualified public accountant for this plan | 2021-12-31 | Unqualified |
| Accountancy firm name | 2021-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2021-12-31 | 134008324 |
| 2020 : BIOGEN 401(K) SAVINGS PLAN 2020 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2020-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2020-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2020-12-31 | $0 |
| Total transfer of assets to this plan | 2020-12-31 | $0 |
| Total transfer of assets from this plan | 2020-12-31 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2020-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2020-12-31 | $0 |
| Expenses. Interest paid | 2020-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2020-12-31 | $0 |
| Total income from all sources (including contributions) | 2020-12-31 | $465,840,306 |
| Total loss/gain on sale of assets | 2020-12-31 | $0 |
| Total of all expenses incurred | 2020-12-31 | $109,122,080 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2020-12-31 | $109,815,645 |
| Expenses. Certain deemed distributions of participant loans | 2020-12-31 | $22,286 |
| Value of total corrective distributions | 2020-12-31 | $203,957 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2020-12-31 | $151,121,462 |
| Value of total assets at end of year | 2020-12-31 | $1,702,688,045 |
| Value of total assets at beginning of year | 2020-12-31 | $1,345,969,819 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2020-12-31 | $-919,808 |
| Total income from rents | 2020-12-31 | $0 |
| Total interest from all sources | 2020-12-31 | $786,455 |
| Total dividends received (eg from common stock, registered investment company shares) | 2020-12-31 | $54,093,385 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2020-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2020-12-31 | $54,093,385 |
| Assets. Real estate other than employer real property at end of year | 2020-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2020-12-31 | $0 |
| Administrative expenses professional fees incurred | 2020-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2020-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2020-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2020-12-31 | Yes |
| Value of fidelity bond cover | 2020-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2020-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2020-12-31 | No |
| Contributions received from participants | 2020-12-31 | $69,341,222 |
| Participant contributions at end of year | 2020-12-31 | $11,023,896 |
| Participant contributions at beginning of year | 2020-12-31 | $10,020,610 |
| Participant contributions at end of year | 2020-12-31 | $0 |
| Participant contributions at beginning of year | 2020-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2020-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2020-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2020-12-31 | $32,983,524 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2020-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2020-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2020-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2020-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2020-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2020-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2020-12-31 | $0 |
| Other income not declared elsewhere | 2020-12-31 | $0 |
| Administrative expenses (other) incurred | 2020-12-31 | $-919,808 |
| Liabilities. Value of operating payables at end of year | 2020-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2020-12-31 | $0 |
| Total non interest bearing cash at end of year | 2020-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2020-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2020-12-31 | No |
| Income. Non cash contributions | 2020-12-31 | $0 |
| Value of net income/loss | 2020-12-31 | $356,718,226 |
| Value of net assets at end of year (total assets less liabilities) | 2020-12-31 | $1,702,688,045 |
| Value of net assets at beginning of year (total assets less liabilities) | 2020-12-31 | $1,345,969,819 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2020-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2020-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2020-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2020-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2020-12-31 | $0 |
| Investment advisory and management fees | 2020-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2020-12-31 | $1,275,308,491 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2020-12-31 | $1,040,498,411 |
| Value of interest in pooled separate accounts at end of year | 2020-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2020-12-31 | $0 |
| Interest on participant loans | 2020-12-31 | $554,874 |
| Income. Interest from loans (other than to participants) | 2020-12-31 | $0 |
| Interest earned on other investments | 2020-12-31 | $0 |
| Income. Interest from US Government securities | 2020-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2020-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2020-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2020-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2020-12-31 | $350,361,588 |
| Value of interest in common/collective trusts at beginning of year | 2020-12-31 | $243,172,640 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2020-12-31 | $60,512,257 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2020-12-31 | $47,857,808 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2020-12-31 | $47,857,808 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2020-12-31 | $231,581 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2020-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2020-12-31 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at end of year | 2020-12-31 | $0 |
| Value of funds held in insurance company general accounts (unallocated contracts) at beginning of year | 2020-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2020-12-31 | $0 |
| Asset value of US Government securities at end of year | 2020-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2020-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2020-12-31 | $145,569,253 |
| Net investment gain/loss from pooled separate accounts | 2020-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2020-12-31 | $114,269,751 |
| Net gain/loss from 103.12 investment entities | 2020-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2020-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2020-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2020-12-31 | No |
| Assets. Invements in employer securities at end of year | 2020-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2020-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2020-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2020-12-31 | $0 |
| Contributions received in cash from employer | 2020-12-31 | $48,796,716 |
| Employer contributions (assets) at end of year | 2020-12-31 | $5,481,813 |
| Employer contributions (assets) at beginning of year | 2020-12-31 | $4,420,350 |
| Income. Dividends from preferred stock | 2020-12-31 | $0 |
| Income. Dividends from common stock | 2020-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2020-12-31 | $109,815,645 |
| Asset. Corporate debt instrument preferred debt at end of year | 2020-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2020-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2020-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2020-12-31 | $0 |
| Contract administrator fees | 2020-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2020-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2020-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2020-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2020-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2020-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2020-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2020-12-31 | $0 |
| Did the plan have assets held for investment | 2020-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2020-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2020-12-31 | No |
| Aggregate proceeds on sale of assets | 2020-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2020-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2020-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2020-12-31 | $0 |
| Opinion of an independent qualified public accountant for this plan | 2020-12-31 | Disclaimer |
| Accountancy firm name | 2020-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2020-12-31 | 134008324 |
| 2019 : BIOGEN 401(K) SAVINGS PLAN 2019 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2019-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2019-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2019-12-31 | $0 |
| Total transfer of assets to this plan | 2019-12-31 | $569,249 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2019-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2019-12-31 | $0 |
| Expenses. Interest paid | 2019-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2019-12-31 | $0 |
| Total income from all sources (including contributions) | 2019-12-31 | $391,210,417 |
| Total loss/gain on sale of assets | 2019-12-31 | $0 |
| Total of all expenses incurred | 2019-12-31 | $92,961,223 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2019-12-31 | $92,725,762 |
| Expenses. Certain deemed distributions of participant loans | 2019-12-31 | $32,670 |
| Value of total corrective distributions | 2019-12-31 | $169,656 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2019-12-31 | $113,812,395 |
| Value of total assets at end of year | 2019-12-31 | $1,345,969,819 |
| Value of total assets at beginning of year | 2019-12-31 | $1,047,151,376 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2019-12-31 | $33,135 |
| Total income from rents | 2019-12-31 | $0 |
| Total interest from all sources | 2019-12-31 | $1,504,164 |
| Total dividends received (eg from common stock, registered investment company shares) | 2019-12-31 | $51,004,456 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2019-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2019-12-31 | $51,004,456 |
| Assets. Real estate other than employer real property at end of year | 2019-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2019-12-31 | $0 |
| Administrative expenses professional fees incurred | 2019-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2019-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2019-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2019-12-31 | Yes |
| Value of fidelity bond cover | 2019-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2019-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2019-12-31 | No |
| Contributions received from participants | 2019-12-31 | $58,673,503 |
| Participant contributions at end of year | 2019-12-31 | $10,020,610 |
| Participant contributions at beginning of year | 2019-12-31 | $10,644,012 |
| Participant contributions at end of year | 2019-12-31 | $0 |
| Participant contributions at beginning of year | 2019-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2019-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2019-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2019-12-31 | $13,370,419 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2019-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2019-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2019-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2019-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2019-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2019-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2019-12-31 | $0 |
| Other income not declared elsewhere | 2019-12-31 | $866,578 |
| Administrative expenses (other) incurred | 2019-12-31 | $33,135 |
| Liabilities. Value of operating payables at end of year | 2019-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2019-12-31 | $0 |
| Total non interest bearing cash at end of year | 2019-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2019-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2019-12-31 | No |
| Income. Non cash contributions | 2019-12-31 | $0 |
| Value of net income/loss | 2019-12-31 | $298,249,194 |
| Value of net assets at end of year (total assets less liabilities) | 2019-12-31 | $1,345,969,819 |
| Value of net assets at beginning of year (total assets less liabilities) | 2019-12-31 | $1,047,151,376 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2019-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2019-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2019-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2019-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2019-12-31 | $0 |
| Investment advisory and management fees | 2019-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2019-12-31 | $1,040,498,411 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2019-12-31 | $798,193,355 |
| Value of interest in pooled separate accounts at end of year | 2019-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2019-12-31 | $0 |
| Interest on participant loans | 2019-12-31 | $568,535 |
| Income. Interest from loans (other than to participants) | 2019-12-31 | $0 |
| Interest earned on other investments | 2019-12-31 | $0 |
| Income. Interest from US Government securities | 2019-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2019-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2019-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2019-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2019-12-31 | $243,172,640 |
| Value of interest in common/collective trusts at beginning of year | 2019-12-31 | $196,321,529 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2019-12-31 | $47,857,808 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2019-12-31 | $37,908,890 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2019-12-31 | $37,908,890 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2019-12-31 | $935,629 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2019-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2019-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2019-12-31 | $0 |
| Asset value of US Government securities at end of year | 2019-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2019-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2019-12-31 | $158,945,523 |
| Net investment gain/loss from pooled separate accounts | 2019-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2019-12-31 | $65,077,301 |
| Net gain/loss from 103.12 investment entities | 2019-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2019-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2019-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2019-12-31 | No |
| Assets. Invements in employer securities at end of year | 2019-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2019-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2019-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2019-12-31 | $0 |
| Contributions received in cash from employer | 2019-12-31 | $41,768,473 |
| Employer contributions (assets) at end of year | 2019-12-31 | $4,420,350 |
| Employer contributions (assets) at beginning of year | 2019-12-31 | $4,083,590 |
| Income. Dividends from preferred stock | 2019-12-31 | $0 |
| Income. Dividends from common stock | 2019-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2019-12-31 | $92,725,762 |
| Asset. Corporate debt instrument preferred debt at end of year | 2019-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2019-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2019-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2019-12-31 | $0 |
| Contract administrator fees | 2019-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2019-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2019-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2019-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2019-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2019-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2019-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2019-12-31 | $0 |
| Did the plan have assets held for investment | 2019-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2019-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2019-12-31 | No |
| Aggregate proceeds on sale of assets | 2019-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2019-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2019-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2019-12-31 | $0 |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2019-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2019-12-31 | Disclaimer |
| Accountancy firm name | 2019-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2019-12-31 | 134008324 |
| 2018 : BIOGEN 401(K) SAVINGS PLAN 2018 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2018-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2018-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2018-12-31 | $0 |
| Total transfer of assets to this plan | 2018-12-31 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2018-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2018-12-31 | $0 |
| Expenses. Interest paid | 2018-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2018-12-31 | $0 |
| Total income from all sources (including contributions) | 2018-12-31 | $38,632,346 |
| Total loss/gain on sale of assets | 2018-12-31 | $0 |
| Total of all expenses incurred | 2018-12-31 | $99,622,233 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2018-12-31 | $99,488,867 |
| Expenses. Certain deemed distributions of participant loans | 2018-12-31 | $0 |
| Value of total corrective distributions | 2018-12-31 | $118,821 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2018-12-31 | $107,227,215 |
| Value of total assets at end of year | 2018-12-31 | $1,047,151,376 |
| Value of total assets at beginning of year | 2018-12-31 | $1,108,141,263 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2018-12-31 | $14,545 |
| Total income from rents | 2018-12-31 | $0 |
| Total interest from all sources | 2018-12-31 | $1,151,489 |
| Total dividends received (eg from common stock, registered investment company shares) | 2018-12-31 | $63,971,997 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2018-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2018-12-31 | $63,971,997 |
| Assets. Real estate other than employer real property at end of year | 2018-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2018-12-31 | $0 |
| Administrative expenses professional fees incurred | 2018-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2018-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2018-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2018-12-31 | Yes |
| Value of fidelity bond cover | 2018-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2018-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2018-12-31 | No |
| Contributions received from participants | 2018-12-31 | $55,198,799 |
| Participant contributions at end of year | 2018-12-31 | $10,644,012 |
| Participant contributions at beginning of year | 2018-12-31 | $10,531,079 |
| Participant contributions at end of year | 2018-12-31 | $0 |
| Participant contributions at beginning of year | 2018-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2018-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2018-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2018-12-31 | $12,642,520 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2018-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2018-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2018-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2018-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2018-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2018-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2018-12-31 | $0 |
| Other income not declared elsewhere | 2018-12-31 | $788,184 |
| Administrative expenses (other) incurred | 2018-12-31 | $14,545 |
| Liabilities. Value of operating payables at end of year | 2018-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2018-12-31 | $0 |
| Total non interest bearing cash at end of year | 2018-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2018-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2018-12-31 | No |
| Income. Non cash contributions | 2018-12-31 | $0 |
| Value of net income/loss | 2018-12-31 | $-60,989,887 |
| Value of net assets at end of year (total assets less liabilities) | 2018-12-31 | $1,047,151,376 |
| Value of net assets at beginning of year (total assets less liabilities) | 2018-12-31 | $1,108,141,263 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2018-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2018-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2018-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2018-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2018-12-31 | $0 |
| Investment advisory and management fees | 2018-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2018-12-31 | $798,193,355 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2018-12-31 | $834,771,408 |
| Value of interest in pooled separate accounts at end of year | 2018-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2018-12-31 | $0 |
| Interest on participant loans | 2018-12-31 | $511,683 |
| Income. Interest from loans (other than to participants) | 2018-12-31 | $0 |
| Interest earned on other investments | 2018-12-31 | $0 |
| Income. Interest from US Government securities | 2018-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2018-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2018-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2018-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2018-12-31 | $196,321,529 |
| Value of interest in common/collective trusts at beginning of year | 2018-12-31 | $224,253,385 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2018-12-31 | $37,908,890 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2018-12-31 | $34,398,428 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2018-12-31 | $34,398,428 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2018-12-31 | $639,806 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2018-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2018-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2018-12-31 | $0 |
| Asset value of US Government securities at end of year | 2018-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2018-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2018-12-31 | $-117,969,949 |
| Net investment gain/loss from pooled separate accounts | 2018-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2018-12-31 | $-16,536,590 |
| Net gain/loss from 103.12 investment entities | 2018-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2018-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2018-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2018-12-31 | No |
| Assets. Invements in employer securities at end of year | 2018-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2018-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2018-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2018-12-31 | $0 |
| Contributions received in cash from employer | 2018-12-31 | $39,385,896 |
| Employer contributions (assets) at end of year | 2018-12-31 | $4,083,590 |
| Employer contributions (assets) at beginning of year | 2018-12-31 | $4,186,963 |
| Income. Dividends from preferred stock | 2018-12-31 | $0 |
| Income. Dividends from common stock | 2018-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2018-12-31 | $99,488,867 |
| Asset. Corporate debt instrument preferred debt at end of year | 2018-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2018-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2018-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2018-12-31 | $0 |
| Contract administrator fees | 2018-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2018-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2018-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2018-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2018-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2018-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2018-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2018-12-31 | $0 |
| Did the plan have assets held for investment | 2018-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2018-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2018-12-31 | No |
| Aggregate proceeds on sale of assets | 2018-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2018-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2018-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2018-12-31 | $0 |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2018-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2018-12-31 | Disclaimer |
| Accountancy firm name | 2018-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2018-12-31 | 134008324 |
| 2017 : BIOGEN 401(K) SAVINGS PLAN 2017 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2017-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2017-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2017-12-31 | $0 |
| Total transfer of assets to this plan | 2017-12-31 | $0 |
| Total transfer of assets from this plan | 2017-12-31 | $33,887,128 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2017-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2017-12-31 | $0 |
| Expenses. Interest paid | 2017-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2017-12-31 | $0 |
| Total income from all sources (including contributions) | 2017-12-31 | $294,975,922 |
| Total loss/gain on sale of assets | 2017-12-31 | $0 |
| Total of all expenses incurred | 2017-12-31 | $92,932,789 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2017-12-31 | $92,773,269 |
| Expenses. Certain deemed distributions of participant loans | 2017-12-31 | $6,521 |
| Value of total corrective distributions | 2017-12-31 | $143,359 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2017-12-31 | $104,496,730 |
| Value of total assets at end of year | 2017-12-31 | $1,108,141,263 |
| Value of total assets at beginning of year | 2017-12-31 | $939,985,258 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2017-12-31 | $9,640 |
| Total income from rents | 2017-12-31 | $0 |
| Total interest from all sources | 2017-12-31 | $763,194 |
| Total dividends received (eg from common stock, registered investment company shares) | 2017-12-31 | $48,876,465 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2017-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2017-12-31 | $48,876,465 |
| Assets. Real estate other than employer real property at end of year | 2017-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2017-12-31 | $0 |
| Administrative expenses professional fees incurred | 2017-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2017-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2017-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2017-12-31 | Yes |
| Value of fidelity bond cover | 2017-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2017-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2017-12-31 | No |
| Contributions received from participants | 2017-12-31 | $53,040,593 |
| Participant contributions at end of year | 2017-12-31 | $10,531,079 |
| Participant contributions at beginning of year | 2017-12-31 | $11,370,991 |
| Participant contributions at end of year | 2017-12-31 | $0 |
| Participant contributions at beginning of year | 2017-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2017-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2017-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2017-12-31 | $12,694,402 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2017-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2017-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2017-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2017-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2017-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2017-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2017-12-31 | $0 |
| Other income not declared elsewhere | 2017-12-31 | $641,806 |
| Administrative expenses (other) incurred | 2017-12-31 | $9,640 |
| Liabilities. Value of operating payables at end of year | 2017-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2017-12-31 | $0 |
| Total non interest bearing cash at end of year | 2017-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2017-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2017-12-31 | No |
| Income. Non cash contributions | 2017-12-31 | $0 |
| Value of net income/loss | 2017-12-31 | $202,043,133 |
| Value of net assets at end of year (total assets less liabilities) | 2017-12-31 | $1,108,141,263 |
| Value of net assets at beginning of year (total assets less liabilities) | 2017-12-31 | $939,985,258 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2017-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2017-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2017-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2017-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2017-12-31 | $0 |
| Investment advisory and management fees | 2017-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2017-12-31 | $834,771,408 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2017-12-31 | $703,291,908 |
| Value of interest in pooled separate accounts at end of year | 2017-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2017-12-31 | $0 |
| Interest on participant loans | 2017-12-31 | $467,382 |
| Income. Interest from loans (other than to participants) | 2017-12-31 | $0 |
| Interest earned on other investments | 2017-12-31 | $0 |
| Income. Interest from US Government securities | 2017-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2017-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2017-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2017-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2017-12-31 | $224,253,385 |
| Value of interest in common/collective trusts at beginning of year | 2017-12-31 | $186,751,887 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2017-12-31 | $34,398,428 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2017-12-31 | $34,318,686 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2017-12-31 | $34,318,686 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2017-12-31 | $295,812 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2017-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2017-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2017-12-31 | $0 |
| Asset value of US Government securities at end of year | 2017-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2017-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2017-12-31 | $85,675,100 |
| Net investment gain/loss from pooled separate accounts | 2017-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2017-12-31 | $54,522,627 |
| Net gain/loss from 103.12 investment entities | 2017-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2017-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2017-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2017-12-31 | No |
| Assets. Invements in employer securities at end of year | 2017-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2017-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2017-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2017-12-31 | $0 |
| Contributions received in cash from employer | 2017-12-31 | $38,761,735 |
| Employer contributions (assets) at end of year | 2017-12-31 | $4,186,963 |
| Employer contributions (assets) at beginning of year | 2017-12-31 | $4,251,786 |
| Income. Dividends from preferred stock | 2017-12-31 | $0 |
| Income. Dividends from common stock | 2017-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2017-12-31 | $92,773,269 |
| Asset. Corporate debt instrument preferred debt at end of year | 2017-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2017-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2017-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2017-12-31 | $0 |
| Contract administrator fees | 2017-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2017-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2017-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2017-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2017-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2017-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2017-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2017-12-31 | $0 |
| Did the plan have assets held for investment | 2017-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2017-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2017-12-31 | No |
| Aggregate proceeds on sale of assets | 2017-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2017-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2017-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2017-12-31 | $0 |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2017-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2017-12-31 | Disclaimer |
| Accountancy firm name | 2017-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2017-12-31 | 134008324 |
| 2016 : BIOGEN 401(K) SAVINGS PLAN 2016 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2016-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2016-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2016-12-31 | $0 |
| Total transfer of assets to this plan | 2016-12-31 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2016-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2016-12-31 | $0 |
| Expenses. Interest paid | 2016-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2016-12-31 | $0 |
| Total income from all sources (including contributions) | 2016-12-31 | $167,777,611 |
| Total loss/gain on sale of assets | 2016-12-31 | $0 |
| Total of all expenses incurred | 2016-12-31 | $100,741,928 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2016-12-31 | $101,118,534 |
| Expenses. Certain deemed distributions of participant loans | 2016-12-31 | $0 |
| Value of total corrective distributions | 2016-12-31 | $32,701 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2016-12-31 | $103,126,813 |
| Value of total assets at end of year | 2016-12-31 | $939,985,258 |
| Value of total assets at beginning of year | 2016-12-31 | $872,949,575 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2016-12-31 | $-409,307 |
| Total income from rents | 2016-12-31 | $0 |
| Total interest from all sources | 2016-12-31 | $611,664 |
| Total dividends received (eg from common stock, registered investment company shares) | 2016-12-31 | $26,509,009 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2016-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2016-12-31 | $26,509,009 |
| Assets. Real estate other than employer real property at end of year | 2016-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2016-12-31 | $0 |
| Administrative expenses professional fees incurred | 2016-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2016-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2016-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2016-12-31 | Yes |
| Value of fidelity bond cover | 2016-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2016-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2016-12-31 | No |
| Contributions received from participants | 2016-12-31 | $53,284,997 |
| Participant contributions at end of year | 2016-12-31 | $11,370,991 |
| Participant contributions at beginning of year | 2016-12-31 | $11,631,833 |
| Participant contributions at end of year | 2016-12-31 | $0 |
| Participant contributions at beginning of year | 2016-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2016-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2016-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2016-12-31 | $10,633,085 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2016-12-31 | $425,859 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2016-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2016-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2016-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2016-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2016-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2016-12-31 | $0 |
| Other income not declared elsewhere | 2016-12-31 | $409,307 |
| Administrative expenses (other) incurred | 2016-12-31 | $-409,307 |
| Liabilities. Value of operating payables at end of year | 2016-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2016-12-31 | $0 |
| Total non interest bearing cash at end of year | 2016-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2016-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2016-12-31 | No |
| Income. Non cash contributions | 2016-12-31 | $0 |
| Value of net income/loss | 2016-12-31 | $67,035,683 |
| Value of net assets at end of year (total assets less liabilities) | 2016-12-31 | $939,985,258 |
| Value of net assets at beginning of year (total assets less liabilities) | 2016-12-31 | $872,949,575 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2016-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2016-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2016-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2016-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2016-12-31 | $0 |
| Investment advisory and management fees | 2016-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2016-12-31 | $703,291,908 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2016-12-31 | $626,817,920 |
| Value of interest in pooled separate accounts at end of year | 2016-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2016-12-31 | $0 |
| Interest on participant loans | 2016-12-31 | $469,060 |
| Income. Interest from loans (other than to participants) | 2016-12-31 | $0 |
| Interest earned on other investments | 2016-12-31 | $0 |
| Income. Interest from US Government securities | 2016-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2016-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2016-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2016-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2016-12-31 | $186,751,887 |
| Value of interest in common/collective trusts at beginning of year | 2016-12-31 | $199,763,626 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2016-12-31 | $34,318,686 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2016-12-31 | $30,070,097 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2016-12-31 | $30,070,097 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2016-12-31 | $142,604 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2016-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2016-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2016-12-31 | $0 |
| Asset value of US Government securities at end of year | 2016-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2016-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2016-12-31 | $28,148,421 |
| Net investment gain/loss from pooled separate accounts | 2016-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2016-12-31 | $8,972,397 |
| Net gain/loss from 103.12 investment entities | 2016-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2016-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2016-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2016-12-31 | No |
| Assets. Invements in employer securities at end of year | 2016-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2016-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2016-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2016-12-31 | $0 |
| Contributions received in cash from employer | 2016-12-31 | $39,208,731 |
| Employer contributions (assets) at end of year | 2016-12-31 | $4,251,786 |
| Employer contributions (assets) at beginning of year | 2016-12-31 | $4,666,099 |
| Income. Dividends from preferred stock | 2016-12-31 | $0 |
| Income. Dividends from common stock | 2016-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2016-12-31 | $100,692,675 |
| Asset. Corporate debt instrument preferred debt at end of year | 2016-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2016-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2016-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2016-12-31 | $0 |
| Contract administrator fees | 2016-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2016-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2016-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2016-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2016-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2016-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2016-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2016-12-31 | $0 |
| Did the plan have assets held for investment | 2016-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2016-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2016-12-31 | No |
| Aggregate proceeds on sale of assets | 2016-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2016-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2016-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2016-12-31 | $0 |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2016-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2016-12-31 | Disclaimer |
| Accountancy firm name | 2016-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2016-12-31 | 134008324 |
| 2015 : BIOGEN 401(K) SAVINGS PLAN 2015 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2015-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2015-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2015-12-31 | $0 |
| Total transfer of assets to this plan | 2015-12-31 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2015-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2015-12-31 | $0 |
| Expenses. Interest paid | 2015-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2015-12-31 | $0 |
| Total income from all sources (including contributions) | 2015-12-31 | $132,978,161 |
| Total loss/gain on sale of assets | 2015-12-31 | $0 |
| Total of all expenses incurred | 2015-12-31 | $83,882,445 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2015-12-31 | $84,065,392 |
| Expenses. Certain deemed distributions of participant loans | 2015-12-31 | $6,530 |
| Value of total corrective distributions | 2015-12-31 | $159,001 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2015-12-31 | $119,911,704 |
| Value of total assets at end of year | 2015-12-31 | $872,949,575 |
| Value of total assets at beginning of year | 2015-12-31 | $823,853,859 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2015-12-31 | $-348,478 |
| Total income from rents | 2015-12-31 | $0 |
| Total interest from all sources | 2015-12-31 | $497,218 |
| Total dividends received (eg from common stock, registered investment company shares) | 2015-12-31 | $40,113,439 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2015-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2015-12-31 | $40,113,439 |
| Assets. Real estate other than employer real property at end of year | 2015-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2015-12-31 | $0 |
| Administrative expenses professional fees incurred | 2015-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2015-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2015-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2015-12-31 | Yes |
| Value of fidelity bond cover | 2015-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2015-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2015-12-31 | No |
| Contributions received from participants | 2015-12-31 | $60,581,530 |
| Participant contributions at end of year | 2015-12-31 | $11,631,833 |
| Participant contributions at beginning of year | 2015-12-31 | $10,337,084 |
| Participant contributions at end of year | 2015-12-31 | $0 |
| Participant contributions at beginning of year | 2015-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2015-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2015-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2015-12-31 | $14,787,122 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2015-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2015-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2015-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2015-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2015-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2015-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2015-12-31 | $0 |
| Other income not declared elsewhere | 2015-12-31 | $0 |
| Administrative expenses (other) incurred | 2015-12-31 | $-348,478 |
| Liabilities. Value of operating payables at end of year | 2015-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2015-12-31 | $0 |
| Total non interest bearing cash at end of year | 2015-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2015-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2015-12-31 | No |
| Income. Non cash contributions | 2015-12-31 | $0 |
| Value of net income/loss | 2015-12-31 | $49,095,716 |
| Value of net assets at end of year (total assets less liabilities) | 2015-12-31 | $872,949,575 |
| Value of net assets at beginning of year (total assets less liabilities) | 2015-12-31 | $823,853,859 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2015-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2015-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2015-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2015-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2015-12-31 | $0 |
| Investment advisory and management fees | 2015-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2015-12-31 | $626,817,920 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2015-12-31 | $581,986,440 |
| Value of interest in pooled separate accounts at end of year | 2015-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2015-12-31 | $0 |
| Interest on participant loans | 2015-12-31 | $470,616 |
| Income. Interest from loans (other than to participants) | 2015-12-31 | $0 |
| Interest earned on other investments | 2015-12-31 | $0 |
| Income. Interest from US Government securities | 2015-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2015-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2015-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2015-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2015-12-31 | $199,763,626 |
| Value of interest in common/collective trusts at beginning of year | 2015-12-31 | $197,550,785 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2015-12-31 | $30,070,097 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2015-12-31 | $29,634,357 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2015-12-31 | $29,634,357 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2015-12-31 | $26,602 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2015-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2015-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2015-12-31 | $0 |
| Asset value of US Government securities at end of year | 2015-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2015-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2015-12-31 | $-37,431,153 |
| Net investment gain/loss from pooled separate accounts | 2015-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2015-12-31 | $9,886,953 |
| Net gain/loss from 103.12 investment entities | 2015-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2015-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2015-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2015-12-31 | No |
| Assets. Invements in employer securities at end of year | 2015-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2015-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2015-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2015-12-31 | $0 |
| Contributions received in cash from employer | 2015-12-31 | $44,543,052 |
| Employer contributions (assets) at end of year | 2015-12-31 | $4,666,099 |
| Employer contributions (assets) at beginning of year | 2015-12-31 | $4,345,193 |
| Income. Dividends from preferred stock | 2015-12-31 | $0 |
| Income. Dividends from common stock | 2015-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2015-12-31 | $84,065,392 |
| Asset. Corporate debt instrument preferred debt at end of year | 2015-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2015-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2015-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2015-12-31 | $0 |
| Contract administrator fees | 2015-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2015-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2015-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2015-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2015-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2015-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2015-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2015-12-31 | $0 |
| Did the plan have assets held for investment | 2015-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2015-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2015-12-31 | No |
| Aggregate proceeds on sale of assets | 2015-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2015-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2015-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2015-12-31 | $0 |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2015-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2015-12-31 | Disclaimer |
| Accountancy firm name | 2015-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2015-12-31 | 134008324 |
| 2014 : BIOGEN 401(K) SAVINGS PLAN 2014 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2014-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2014-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2014-12-31 | $0 |
| Total transfer of assets to this plan | 2014-12-31 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2014-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2014-12-31 | $0 |
| Expenses. Interest paid | 2014-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2014-12-31 | $0 |
| Total income from all sources (including contributions) | 2014-12-31 | $158,197,309 |
| Total loss/gain on sale of assets | 2014-12-31 | $0 |
| Total of all expenses incurred | 2014-12-31 | $49,870,960 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2014-12-31 | $49,649,099 |
| Expenses. Certain deemed distributions of participant loans | 2014-12-31 | $34,867 |
| Value of total corrective distributions | 2014-12-31 | $146,207 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2014-12-31 | $103,829,170 |
| Value of total assets at end of year | 2014-12-31 | $823,853,859 |
| Value of total assets at beginning of year | 2014-12-31 | $715,527,510 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2014-12-31 | $40,787 |
| Total income from rents | 2014-12-31 | $0 |
| Total interest from all sources | 2014-12-31 | $421,599 |
| Total dividends received (eg from common stock, registered investment company shares) | 2014-12-31 | $46,010,779 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2014-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2014-12-31 | $46,010,779 |
| Assets. Real estate other than employer real property at end of year | 2014-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2014-12-31 | $0 |
| Administrative expenses professional fees incurred | 2014-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2014-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2014-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2014-12-31 | Yes |
| Value of fidelity bond cover | 2014-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2014-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2014-12-31 | No |
| Contributions received from participants | 2014-12-31 | $52,749,045 |
| Participant contributions at end of year | 2014-12-31 | $10,337,084 |
| Participant contributions at beginning of year | 2014-12-31 | $8,890,260 |
| Participant contributions at end of year | 2014-12-31 | $0 |
| Participant contributions at beginning of year | 2014-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2014-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2014-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2014-12-31 | $12,192,270 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2014-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2014-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2014-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2014-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2014-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2014-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2014-12-31 | $0 |
| Other income not declared elsewhere | 2014-12-31 | $431,155 |
| Administrative expenses (other) incurred | 2014-12-31 | $40,787 |
| Liabilities. Value of operating payables at end of year | 2014-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2014-12-31 | $0 |
| Total non interest bearing cash at end of year | 2014-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2014-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2014-12-31 | No |
| Income. Non cash contributions | 2014-12-31 | $0 |
| Value of net income/loss | 2014-12-31 | $108,326,349 |
| Value of net assets at end of year (total assets less liabilities) | 2014-12-31 | $823,853,859 |
| Value of net assets at beginning of year (total assets less liabilities) | 2014-12-31 | $715,527,510 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2014-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2014-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2014-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2014-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2014-12-31 | $0 |
| Investment advisory and management fees | 2014-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2014-12-31 | $581,986,440 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2014-12-31 | $673,386,814 |
| Value of interest in pooled separate accounts at end of year | 2014-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2014-12-31 | $0 |
| Interest on participant loans | 2014-12-31 | $389,006 |
| Income. Interest from loans (other than to participants) | 2014-12-31 | $0 |
| Interest earned on other investments | 2014-12-31 | $0 |
| Income. Interest from US Government securities | 2014-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2014-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2014-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2014-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2014-12-31 | $197,550,785 |
| Value of interest in common/collective trusts at beginning of year | 2014-12-31 | $0 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2014-12-31 | $29,634,357 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2014-12-31 | $29,447,954 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2014-12-31 | $29,447,954 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2014-12-31 | $32,593 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2014-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2014-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2014-12-31 | $0 |
| Asset value of US Government securities at end of year | 2014-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2014-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2014-12-31 | $-5,522,280 |
| Net investment gain/loss from pooled separate accounts | 2014-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2014-12-31 | $13,026,886 |
| Net gain/loss from 103.12 investment entities | 2014-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2014-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2014-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2014-12-31 | No |
| Assets. Invements in employer securities at end of year | 2014-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2014-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2014-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2014-12-31 | $0 |
| Contributions received in cash from employer | 2014-12-31 | $38,887,855 |
| Employer contributions (assets) at end of year | 2014-12-31 | $4,345,193 |
| Employer contributions (assets) at beginning of year | 2014-12-31 | $3,802,482 |
| Income. Dividends from preferred stock | 2014-12-31 | $0 |
| Income. Dividends from common stock | 2014-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2014-12-31 | $49,649,099 |
| Asset. Corporate debt instrument preferred debt at end of year | 2014-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2014-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2014-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2014-12-31 | $0 |
| Contract administrator fees | 2014-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2014-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2014-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2014-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2014-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2014-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2014-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2014-12-31 | $0 |
| Did the plan have assets held for investment | 2014-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2014-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2014-12-31 | No |
| Aggregate proceeds on sale of assets | 2014-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2014-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2014-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2014-12-31 | $0 |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2014-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2014-12-31 | Disclaimer |
| Accountancy firm name | 2014-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2014-12-31 | 134008324 |
| 2013 : BIOGEN 401(K) SAVINGS PLAN 2013 401k financial data |
|---|
| Unrealized appreciation/depreciation of real estate assets | 2013-12-31 | $0 |
| Unrealized appreciation/depreciation of other (non real estate) assets | 2013-12-31 | $0 |
| Total unrealized appreciation/depreciation of assets | 2013-12-31 | $0 |
| Total transfer of assets to this plan | 2013-12-31 | $0 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2013-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2013-12-31 | $0 |
| Expenses. Interest paid | 2013-12-31 | $0 |
| Amount of participant contributions which was failed to transmit to the plan within the time period described in 29 CFR 251.3-102 | 2013-12-31 | $0 |
| Total income from all sources (including contributions) | 2013-12-31 | $224,771,161 |
| Total loss/gain on sale of assets | 2013-12-31 | $0 |
| Total of all expenses incurred | 2013-12-31 | $38,988,977 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2013-12-31 | $39,104,893 |
| Expenses. Certain deemed distributions of participant loans | 2013-12-31 | $1,469 |
| Value of total corrective distributions | 2013-12-31 | $109,714 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2013-12-31 | $91,275,926 |
| Value of total assets at end of year | 2013-12-31 | $715,527,510 |
| Value of total assets at beginning of year | 2013-12-31 | $529,745,326 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2013-12-31 | $-227,099 |
| Total income from rents | 2013-12-31 | $0 |
| Total interest from all sources | 2013-12-31 | $367,952 |
| Total dividends received (eg from common stock, registered investment company shares) | 2013-12-31 | $33,039,361 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2013-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2013-12-31 | $33,039,361 |
| Assets. Real estate other than employer real property at end of year | 2013-12-31 | $0 |
| Assets. Real estate other than employer real property at beginning of year | 2013-12-31 | $0 |
| Administrative expenses professional fees incurred | 2013-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at end of year | 2013-12-31 | $0 |
| Assets. Corporate prefeered stocks other than exployer securities at beginning of year | 2013-12-31 | $0 |
| Was this plan covered by a fidelity bond | 2013-12-31 | Yes |
| Value of fidelity bond cover | 2013-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2013-12-31 | No |
| Were there any nonexempt tranactions with any party-in-interest | 2013-12-31 | No |
| Contributions received from participants | 2013-12-31 | $45,953,069 |
| Participant contributions at end of year | 2013-12-31 | $8,890,260 |
| Participant contributions at beginning of year | 2013-12-31 | $7,784,009 |
| Participant contributions at end of year | 2013-12-31 | $0 |
| Participant contributions at beginning of year | 2013-12-31 | $0 |
| Assets. Other investments not covered elsewhere at end of year | 2013-12-31 | $0 |
| Assets. Other investments not covered elsewhere at beginning of year | 2013-12-31 | $0 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2013-12-31 | $10,570,775 |
| Expenses. Other payments made (not to insurance carriers or or participants/beneficiaries) | 2013-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at end of year | 2013-12-31 | $0 |
| Value of other receiveables (less allowance for doubtful accounts) at beginning of year | 2013-12-31 | $0 |
| Assets. Loans (other than to participants) at end of year | 2013-12-31 | $0 |
| Assets. Loans (other than to participants) at beginning of year | 2013-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at end of year | 2013-12-31 | $0 |
| Other liabilities (not benefit claims, operating payabales oe acquisition indebtedness) at beginning of year | 2013-12-31 | $0 |
| Other income not declared elsewhere | 2013-12-31 | $6,607 |
| Administrative expenses (other) incurred | 2013-12-31 | $-227,099 |
| Liabilities. Value of operating payables at end of year | 2013-12-31 | $0 |
| Liabilities. Value of operating payables at beginning of year | 2013-12-31 | $0 |
| Total non interest bearing cash at end of year | 2013-12-31 | $0 |
| Total non interest bearing cash at beginning of year | 2013-12-31 | $0 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2013-12-31 | No |
| Income. Non cash contributions | 2013-12-31 | $0 |
| Value of net income/loss | 2013-12-31 | $185,782,184 |
| Value of net assets at end of year (total assets less liabilities) | 2013-12-31 | $715,527,510 |
| Value of net assets at beginning of year (total assets less liabilities) | 2013-12-31 | $529,745,326 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2013-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2013-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2013-12-31 | No |
| Assets. partnership/joint venture interests at end of year | 2013-12-31 | $0 |
| Assets. partnership/joint venture interests at beginning of year | 2013-12-31 | $0 |
| Investment advisory and management fees | 2013-12-31 | $0 |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2013-12-31 | $673,386,814 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2013-12-31 | $493,262,027 |
| Value of interest in pooled separate accounts at end of year | 2013-12-31 | $0 |
| Value of interest in pooled separate accounts at beginning of year | 2013-12-31 | $0 |
| Interest on participant loans | 2013-12-31 | $349,753 |
| Income. Interest from loans (other than to participants) | 2013-12-31 | $0 |
| Interest earned on other investments | 2013-12-31 | $0 |
| Income. Interest from US Government securities | 2013-12-31 | $0 |
| Income. Interest from corporate debt instruments | 2013-12-31 | $0 |
| Value of interest in master investment trust accounts at end of year | 2013-12-31 | $0 |
| Value of interest in master investment trust accounts at beginning of year | 2013-12-31 | $0 |
| Value of interest in common/collective trusts at end of year | 2013-12-31 | $0 |
| Value of interest in common/collective trusts at beginning of year | 2013-12-31 | $0 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2013-12-31 | $29,447,954 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2013-12-31 | $26,159,195 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2013-12-31 | $26,159,195 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2013-12-31 | $18,199 |
| Assets. Value of investments in 103.12 investment entities at end of year | 2013-12-31 | $0 |
| Assets. Value of investments in 103.12 investment entities at beginning of year | 2013-12-31 | $0 |
| Expenses. Payments to insurance carriers foe the provision of benefits | 2013-12-31 | $0 |
| Asset value of US Government securities at end of year | 2013-12-31 | $0 |
| Asset value of US Government securities at beginning of year | 2013-12-31 | $0 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2013-12-31 | $100,081,315 |
| Net investment gain/loss from pooled separate accounts | 2013-12-31 | $0 |
| Net investment gain or loss from common/collective trusts | 2013-12-31 | $0 |
| Net gain/loss from 103.12 investment entities | 2013-12-31 | $0 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2013-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2013-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2013-12-31 | No |
| Assets. Invements in employer securities at end of year | 2013-12-31 | $0 |
| Assets. Invements in employer securities at beginning of year | 2013-12-31 | $0 |
| Assets. Value of employer real property at end of year | 2013-12-31 | $0 |
| Assets. Value of employer real property at beginning of year | 2013-12-31 | $0 |
| Contributions received in cash from employer | 2013-12-31 | $34,752,082 |
| Employer contributions (assets) at end of year | 2013-12-31 | $3,802,482 |
| Employer contributions (assets) at beginning of year | 2013-12-31 | $2,540,095 |
| Income. Dividends from preferred stock | 2013-12-31 | $0 |
| Income. Dividends from common stock | 2013-12-31 | $0 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2013-12-31 | $39,104,893 |
| Asset. Corporate debt instrument preferred debt at end of year | 2013-12-31 | $0 |
| Asset. Corporate debt instrument preferred debt at beginning of year | 2013-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at end of year | 2013-12-31 | $0 |
| Asset. Corporate debt instrument debt (other) at beginning of year | 2013-12-31 | $0 |
| Contract administrator fees | 2013-12-31 | $0 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2013-12-31 | No |
| Assets. Corporate common stocks other than exployer securities at end of year | 2013-12-31 | $0 |
| Assets. Corporate common stocks other than exployer securities at beginning of year | 2013-12-31 | $0 |
| Liabilities. Value of benefit claims payable at end of year | 2013-12-31 | $0 |
| Liabilities. Value of benefit claims payable at beginning of year | 2013-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at end of year | 2013-12-31 | $0 |
| Assets. Value of buildings and other operty used in plan operation at beginning of year | 2013-12-31 | $0 |
| Did the plan have assets held for investment | 2013-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2013-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2013-12-31 | No |
| Aggregate proceeds on sale of assets | 2013-12-31 | $0 |
| Aggregate carrying amount (costs) on sale of assets | 2013-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at end of year | 2013-12-31 | $0 |
| Liabilities. Value of acquisition indebtedness at beginning of year | 2013-12-31 | $0 |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2013-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2013-12-31 | Disclaimer |
| Accountancy firm name | 2013-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2013-12-31 | 134008324 |
| 2012 : BIOGEN 401(K) SAVINGS PLAN 2012 401k financial data |
|---|
| Total transfer of assets to this plan | 2012-12-31 | $562,705 |
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2012-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2012-12-31 | $0 |
| Total income from all sources (including contributions) | 2012-12-31 | $135,386,428 |
| Total of all expenses incurred | 2012-12-31 | $46,033,526 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2012-12-31 | $46,146,011 |
| Expenses. Certain deemed distributions of participant loans | 2012-12-31 | $11,956 |
| Value of total corrective distributions | 2012-12-31 | $53,853 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2012-12-31 | $75,827,006 |
| Value of total assets at end of year | 2012-12-31 | $529,745,326 |
| Value of total assets at beginning of year | 2012-12-31 | $439,829,719 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2012-12-31 | $-178,294 |
| Total interest from all sources | 2012-12-31 | $339,989 |
| Total dividends received (eg from common stock, registered investment company shares) | 2012-12-31 | $18,503,121 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2012-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2012-12-31 | $18,503,121 |
| Was this plan covered by a fidelity bond | 2012-12-31 | Yes |
| Value of fidelity bond cover | 2012-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2012-12-31 | No |
| Total value of distributions paid in property other than in cash, annuity contracts, or publicly traded employer securities | 2012-12-31 | $0 |
| Were there any nonexempt tranactions with any party-in-interest | 2012-12-31 | No |
| Contributions received from participants | 2012-12-31 | $37,830,177 |
| Participant contributions at end of year | 2012-12-31 | $7,784,009 |
| Participant contributions at beginning of year | 2012-12-31 | $6,701,147 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2012-12-31 | $10,182,611 |
| Other income not declared elsewhere | 2012-12-31 | $15,674 |
| Administrative expenses (other) incurred | 2012-12-31 | $-178,294 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2012-12-31 | No |
| Value of net income/loss | 2012-12-31 | $89,352,902 |
| Value of net assets at end of year (total assets less liabilities) | 2012-12-31 | $529,745,326 |
| Value of net assets at beginning of year (total assets less liabilities) | 2012-12-31 | $439,829,719 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2012-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2012-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2012-12-31 | No |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2012-12-31 | $493,262,027 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2012-12-31 | $403,095,401 |
| Interest on participant loans | 2012-12-31 | $311,665 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2012-12-31 | $26,159,195 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2012-12-31 | $27,586,920 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2012-12-31 | $27,586,920 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2012-12-31 | $28,324 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2012-12-31 | $40,700,638 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2012-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2012-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2012-12-31 | No |
| Contributions received in cash from employer | 2012-12-31 | $27,814,218 |
| Employer contributions (assets) at end of year | 2012-12-31 | $2,540,095 |
| Employer contributions (assets) at beginning of year | 2012-12-31 | $2,446,251 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2012-12-31 | $46,146,011 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2012-12-31 | No |
| Did the plan have assets held for investment | 2012-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2012-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2012-12-31 | No |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2012-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2012-12-31 | Disclaimer |
| Accountancy firm name | 2012-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2012-12-31 | 134008324 |
| 2011 : BIOGEN 401(K) SAVINGS PLAN 2011 401k financial data |
|---|
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2011-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2011-12-31 | $0 |
| Total income from all sources (including contributions) | 2011-12-31 | $56,432,125 |
| Total of all expenses incurred | 2011-12-31 | $68,170,110 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2011-12-31 | $68,126,551 |
| Expenses. Certain deemed distributions of participant loans | 2011-12-31 | $1,962 |
| Value of total corrective distributions | 2011-12-31 | $30,130 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2011-12-31 | $61,731,079 |
| Value of total assets at end of year | 2011-12-31 | $439,829,719 |
| Value of total assets at beginning of year | 2011-12-31 | $451,567,704 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2011-12-31 | $11,467 |
| Total interest from all sources | 2011-12-31 | $290,723 |
| Total dividends received (eg from common stock, registered investment company shares) | 2011-12-31 | $16,115,602 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2011-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2011-12-31 | $16,115,602 |
| Was this plan covered by a fidelity bond | 2011-12-31 | Yes |
| Value of fidelity bond cover | 2011-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2011-12-31 | No |
| Total value of distributions paid in property other than in cash, annuity contracts, or publicly traded employer securities | 2011-12-31 | $0 |
| Were there any nonexempt tranactions with any party-in-interest | 2011-12-31 | No |
| Contributions received from participants | 2011-12-31 | $32,905,663 |
| Participant contributions at end of year | 2011-12-31 | $6,701,147 |
| Participant contributions at beginning of year | 2011-12-31 | $6,100,189 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2011-12-31 | $4,876,762 |
| Administrative expenses (other) incurred | 2011-12-31 | $11,467 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2011-12-31 | No |
| Value of net income/loss | 2011-12-31 | $-11,737,985 |
| Value of net assets at end of year (total assets less liabilities) | 2011-12-31 | $439,829,719 |
| Value of net assets at beginning of year (total assets less liabilities) | 2011-12-31 | $451,567,704 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2011-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2011-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2011-12-31 | No |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2011-12-31 | $403,095,401 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2011-12-31 | $416,397,827 |
| Interest on participant loans | 2011-12-31 | $272,736 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2011-12-31 | $27,586,920 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2011-12-31 | $26,549,269 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2011-12-31 | $26,549,269 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2011-12-31 | $17,987 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2011-12-31 | $-21,705,279 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2011-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2011-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2011-12-31 | No |
| Contributions received in cash from employer | 2011-12-31 | $23,948,654 |
| Employer contributions (assets) at end of year | 2011-12-31 | $2,446,251 |
| Employer contributions (assets) at beginning of year | 2011-12-31 | $2,520,419 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2011-12-31 | $68,126,551 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2011-12-31 | No |
| Did the plan have assets held for investment | 2011-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2011-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2011-12-31 | No |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2011-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2011-12-31 | Disclaimer |
| Accountancy firm name | 2011-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2011-12-31 | 134008324 |
| 2010 : BIOGEN 401(K) SAVINGS PLAN 2010 401k financial data |
|---|
| Total liabilities at end of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2010-12-31 | $0 |
| Total liabilities at beginning of year (benefit claims payable, operating payabales, acquisition indebtedness and other liabilities) | 2010-12-31 | $0 |
| Total income from all sources (including contributions) | 2010-12-31 | $119,668,708 |
| Total of all expenses incurred | 2010-12-31 | $23,171,026 |
| Benefit payments and payments to participlants,beneficiaries,insurance carriers and others | 2010-12-31 | $23,031,685 |
| Expenses. Certain deemed distributions of participant loans | 2010-12-31 | $7,123 |
| Value of total corrective distributions | 2010-12-31 | $116,731 |
| Total contributions o plan (from employers,participants, others, non cash contrinutions) | 2010-12-31 | $63,533,917 |
| Value of total assets at end of year | 2010-12-31 | $451,567,704 |
| Value of total assets at beginning of year | 2010-12-31 | $355,070,022 |
| Total of administrative expenses incurred including professional, contract, advisory and management fees | 2010-12-31 | $15,487 |
| Total interest from all sources | 2010-12-31 | $284,891 |
| Total dividends received (eg from common stock, registered investment company shares) | 2010-12-31 | $8,235,210 |
| Has a resolution to terminate the plan been adopted during the plan year or any prior plan year | 2010-12-31 | No |
| Total dividends received from registered investment company shares (eg mutual funds) | 2010-12-31 | $8,235,210 |
| Was this plan covered by a fidelity bond | 2010-12-31 | Yes |
| Value of fidelity bond cover | 2010-12-31 | $10,000,000 |
| If this is an individual account plan, was there a blackout period | 2010-12-31 | No |
| Total value of distributions paid in property other than in cash, annuity contracts, or publicly traded employer securities | 2010-12-31 | $0 |
| Were there any nonexempt tranactions with any party-in-interest | 2010-12-31 | No |
| Contributions received from participants | 2010-12-31 | $34,707,021 |
| Participant contributions at end of year | 2010-12-31 | $6,100,189 |
| Participant contributions at beginning of year | 2010-12-31 | $5,265,588 |
| Income. Received or receivable in cash from other sources (including rollovers) | 2010-12-31 | $3,690,479 |
| Administrative expenses (other) incurred | 2010-12-31 | $15,487 |
| Did the receive any noncash contributions whose value was neither redily determinable on an established market nor set by an independent third party appraiser | 2010-12-31 | No |
| Value of net income/loss | 2010-12-31 | $96,497,682 |
| Value of net assets at end of year (total assets less liabilities) | 2010-12-31 | $451,567,704 |
| Value of net assets at beginning of year (total assets less liabilities) | 2010-12-31 | $355,070,022 |
| Did the plan have a loss casued by fraud or dishonesty (regardless whether reimbursed by fidelity bond) | 2010-12-31 | No |
| Were any loans by the plan or fixed income obligations due to the plan in default | 2010-12-31 | No |
| Were any leases to which the plan was party in default or uncollectible | 2010-12-31 | No |
| Value of interest in registered invesment companies (eg mutual funds) at end of year | 2010-12-31 | $416,397,827 |
| Value of interest in registered invesment companies (eg mutual funds) at beginning of year | 2010-12-31 | $320,473,020 |
| Interest on participant loans | 2010-12-31 | $284,695 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at end of year | 2010-12-31 | $26,549,269 |
| Interest-bearing cash (include money market accounts & certificates of deposit) at beginning of the Year | 2010-12-31 | $27,063,191 |
| Value of interest bearing cash (including money market accounts and certificates of deposits) at beginning of year | 2010-12-31 | $27,063,191 |
| Interest earned from interest bearing cash (including money market accounts and certificates of deposit) | 2010-12-31 | $196 |
| Net investment gain/loss from registered investment companies (e.g. mutual funds) | 2010-12-31 | $47,614,690 |
| Were any plan transactions or series of transactions in excess of 5% of the current value of the plan assets | 2010-12-31 | No |
| Was there a failure to transmit to the plan any participant contributions | 2010-12-31 | No |
| Has the plan failed to provide any benefit when due under the plan | 2010-12-31 | No |
| Contributions received in cash from employer | 2010-12-31 | $25,136,417 |
| Employer contributions (assets) at end of year | 2010-12-31 | $2,520,419 |
| Employer contributions (assets) at beginning of year | 2010-12-31 | $2,268,223 |
| Benefit payments and payments to provide benefits directly to participlants or beneficiaries including direct rollovers | 2010-12-31 | $23,031,685 |
| Was the provided the required notice or one of the exceptions to providing the black out period notice applied under 29 CFR 2520.101-3 | 2010-12-31 | No |
| Did the plan have assets held for investment | 2010-12-31 | Yes |
| Did the plan hold any assets whose current value was neither redily determinable on an established market nor set by an independent third party appraiser | 2010-12-31 | No |
| Were all the plan assets eitehr distributed to particpants/beneficiaries, transferred to another plan or brought under the control of the PBGC | 2010-12-31 | No |
| Accountant perfomed limited scope audit pursuant to 29 CFR 2520.103-8 and/or 103-12(d) | 2010-12-31 | Yes |
| Opinion of an independent qualified public accountant for this plan | 2010-12-31 | Qualified |
| Accountancy firm name | 2010-12-31 | PRICEWATERHOUSECOOPERS |
| Accountancy firm EIN | 2010-12-31 | 134008324 |
| 2009 : BIOGEN 401(K) SAVINGS PLAN 2009 401k financial data |
|---|
| Total value of distributions paid in property other than in cash, annuity contracts, or publicly traded employer securities | 2009-12-31 | $0 |
