BIIB Institutional Ownership & Shareholders
BIOGEN INC (BIIB) is currently held by 1,033 institutional investors tracked by InsiderSet, with a combined reported market value of approximately $32.73B based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026.
Fmr Llc is currently the largest disclosed institutional shareholder of BIIB tracked by InsiderSet, reporting ownership valued at approximately $3.94B in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $4.62B, representing an estimated gain of +17.38% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 62% of the total disclosed BIIB value among the investors covered in this analysis. Major shareholders include Fmr Llc, Blackrock, Inc., Primecap Management Co/Ca/, and several other long-term asset managers with concentrated positions in BIOGEN INC (BIIB).
This page ranks the largest institutional BIIB shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
1,033
Total Reported Value
$32.73B
Largest Holder
Fmr Llc
Largest Position
$3.94B
Insider Transactions (90d)
6
Latest Filing Quarter
Q2 2026
New Institutional Positions
33
Funds Exiting Positions
1
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Fmr Llc | 0.17% | 18,217,239 | $3,936,016,552 | $4,620,256,155 | +$684,239,603 | +17.38% | |
| Blackrock, Inc. | 0.05% | 15,985,736 | $3,453,877,982 | $4,054,302,364 | +$600,424,382 | +17.38% | |
| Primecap Management Co/Ca/ | 1.94% | 15,154,606 | $3,274,304,389 | $3,843,511,174 | +$569,206,785 | +17.38% | |
| Banque Cantonale Vaudoise | 0.34% | 11,496 | $2,484,000,000 | $2,915,616 | -$2,481,084,384 | -99.88% | |
| Vanguard Capital Management Llc | 0.04% | 9,651,117 | $2,085,220,339 | $2,447,716,294 | +$362,495,955 | +17.38% | |
| State Street Corp | 0.05% | 7,344,327 | $1,586,815,292 | $1,862,668,214 | +$275,852,922 | +17.38% | |
| Vanguard Portfolio Management Llc | 0.06% | 6,604,936 | $1,427,062,472 | $1,675,143,868 | +$248,081,396 | +17.38% | |
| Geode Capital Management, Llc | 0.05% | 4,449,295 | $957,935,835 | $1,128,430,198 | +$170,494,363 | +17.80% | |
| Wellington Management Group Llp | 0.12% | 3,117,469 | $673,560,352 | $790,652,488 | +$117,092,136 | +17.38% | |
| Norges Bank | 0.06% | 2,580,033 | $557,441,930 | $654,347,969 | +$96,906,039 | +17.38% | |
| Morgan Stanley | 0.03% | 2,411,271 | $520,979,947 | $611,546,551 | +$90,566,604 | +17.38% | |
| Aqr Capital Management Llc | 0.15% | 1,936,859 | $416,928,075 | $491,226,180 | +$74,298,105 | +17.82% | |
| Jpmorgan Chase & Co | 0.02% | 1,823,140 | $394,947,245 | $462,384,767 | +$67,437,522 | +17.08% | |
| Invesco Ltd. | 0.03% | 1,803,944 | $389,760,120 | $457,516,277 | +$67,756,157 | +17.38% | |
| Legal & General Group Plc | 0.07% | 1,493,289 | $322,640,021 | $378,727,956 | +$56,087,935 | +17.38% | |
| Northern Trust Corp | 0.04% | 1,429,490 | $308,855,610 | $362,547,254 | +$53,691,644 | +17.38% | |
| Boston Partners | 0.24% | 1,263,429 | $272,849,469 | $320,430,863 | +$47,581,394 | +17.44% | |
| Goldman Sachs Group Inc | 0.03% | 1,230,390 | $265,838,021 | $312,051,512 | +$46,213,491 | +17.38% | |
| Ubs Am, A Distinct Business Unit Of Ubs Asset Management Americas Llc | 0.05% | 1,377,568 | $252,549,543 | $349,378,796 | +$96,829,253 | +38.34% | |
| Dimensional Fund Advisors Lp | 0.04% | 1,148,568 | $248,165,892 | $291,299,816 | +$43,133,924 | +17.38% | |
| Pacer Advisors, Inc. | 0.63% | 1,122,981 | $242,631,000 | $284,810,441 | +$42,179,441 | +17.38% | |
| Charles Schwab Investment Management Inc | 0.03% | 1,117,663 | $241,482,267 | $283,461,690 | +$41,979,423 | +17.38% | |
| Bank Of America Corp | 0.02% | 1,116,228 | $241,172,222 | $283,097,745 | +$41,925,523 | +17.38% | |
| Ubs Group Ag | 0.04% | 1,030,150 | $222,574,209 | $261,266,643 | +$38,692,434 | +17.38% | |
| Alyeska Investment Group, L.P. | 0.52% | 932,374 | $201,448,726 | $236,468,694 | +$35,019,968 | +17.38% | |
| Deutsche Bank Ag\ | 0.06% | 894,035 | $193,165,202 | $226,745,157 | +$33,579,955 | +17.38% | |
| Pictet Asset Management Holding Sa | 0.18% | 851,819 | $184,144,886 | $216,038,335 | +$31,893,449 | +17.32% | |
| Vanguard Fiduciary Trust Co | 0.04% | 829,318 | $179,182,447 | $210,331,631 | +$31,149,184 | +17.38% | |
| Fred Alger Management, Llc | 0.57% | 788,307 | $170,321,610 | $199,930,421 | +$29,608,811 | +17.38% | |
| Price T Rowe Associates Inc | 0.02% | 774,283 | $167,293,000 | $196,373,654 | +$29,080,654 | +17.38% | |
| Bank Of New York Mellon Corp | 0.03% | 773,619 | $167,148,200 | $196,205,251 | +$29,057,051 | +17.38% | |
| Massachusetts Financial Services Co | 0.05% | 744,892 | $163,127,433 | $188,919,509 | +$25,792,076 | +15.81% | |
| Citigroup Inc | 0.07% | 734,517 | $158,699,743 | $186,288,202 | +$27,588,459 | +17.38% | |
| Royal Bank Of Canada | 0.03% | 708,562 | $153,093,000 | $179,705,494 | +$26,612,494 | +17.38% | |
| Employees Provident Fund Board | 0.87% | 704,196 | $152,148,588 | $178,598,190 | +$26,449,602 | +17.38% | |
| Robeco Institutional Asset Management B.V. | 0.18% | 656,465 | $148,282,315 | $166,492,653 | +$18,210,338 | +12.28% | |
| First Trust Advisors Lp | 0.09% | 682,021 | $147,357,277 | $172,974,166 | +$25,616,889 | +17.38% | |
| Australiansuper Pty Ltd | 0.63% | 672,723 | $145,348,531 | $170,616,007 | +$25,267,476 | +17.38% | |
| Artemis Investment Management Llp | 1.15% | 581,774 | $131,411,111 | $147,549,522 | +$16,138,411 | +12.28% | |
| Zurcher Kantonalbank (Zurich Cantonalbank) | 0.22% | 540,001 | $116,672,616 | $136,955,054 | +$20,282,438 | +17.38% | |
| Hsbc Holdings Plc | 0.05% | 527,866 | $113,972,342 | $133,877,375 | +$19,905,033 | +17.46% | |
| Caisse De Depot Et Placement Du Quebec | 0.16% | 510,194 | $110,232,516 | $129,395,402 | +$19,162,886 | +17.38% | |
| Lsv Asset Management | 0.17% | 444,049 | $95,941,000 | $112,619,707 | +$16,678,707 | +17.38% | |
| B. Metzler Seel. Sohn & Co. Ag | 0.79% | 403,636 | $91,173,300 | $102,370,162 | +$11,196,862 | +12.28% | |
| Citadel Advisors Llc | 0.05% | 418,356 | $90,389,997 | $106,103,449 | +$15,713,452 | +17.38% | |
| Swiss National Bank | 0.05% | 413,900 | $89,427,234 | $104,973,318 | +$15,546,084 | +17.38% | |
| National Pension Service | 0.06% | 406,064 | $87,734,188 | $102,985,952 | +$15,251,764 | +17.38% | |
| Bnp Paribas Financial Markets | 0.04% | 387,542 | $83,732,325 | $98,288,402 | +$14,556,077 | +17.38% | |
| Candriam S.C.A. | 0.37% | 384,326 | $82,957,583 | $97,472,760 | +$14,515,177 | +17.50% | |
| Mitsubishi Ufj Asset Management Co., Ltd. | 0.04% | 358,823 | $77,527,297 | $91,004,689 | +$13,477,392 | +17.38% |
Frequently asked questions about BIIB
Who are the largest institutional holders of BIIB?
The largest institutional holders of BIIB reported in the latest SEC Form 13F filings include Fmr Llc, Blackrock, Inc., Primecap Management Co/Ca/, Banque Cantonale Vaudoise, and Vanguard Capital Management Llc. InsiderSet ranks institutional holders by their latest reported BIIB position.
What is BIIB institutional ownership?
This page tracks BIIB positions reported by institutional investment managers through SEC Form 13F. BIOGEN INC (BIIB) institutional ownership on InsiderSet reflects disclosed 13F holdings among the managers we analyze, not every shareholder of the stock.
How many institutions own BIIB?
InsiderSet currently tracks 1,033 institutional managers reporting BIIB holdings in the latest available 13F data. This count reflects institutions included in the SEC Form 13F filings analyzed by InsiderSet and should not be interpreted as the total number of BIIB shareholders.
How much BIIB stock do institutions own?
Institutional investment managers disclosed approximately $32.73B in BIIB holdings for Q2 2026. This figure is reported 13F value as of the filing period, not necessarily today's market value.
When was BIIB institutional ownership last updated?
The latest BIIB institutional ownership data on InsiderSet is based on SEC Form 13F filings for the quarter ended June 30, 2026. Form 13F filings are generally reported after the quarter ends, so the holdings shown represent the latest publicly disclosed positions rather than real-time institutional holdings.
Are institutional BIIB holdings real-time?
No. Form 13F data is not real-time. It represents positions reported by institutional investment managers as of the end of the reporting quarter. An institution may have changed its BIIB position after the reporting date.
Are institutions buying or selling BIIB?
Institutional buying and selling can be analyzed by comparing BIIB positions across consecutive 13F reporting periods. InsiderSet's BIIB Ownership Changes page shows institutions that increased, reduced, initiated, or exited positions based on reported 13F holdings. View BIIB ownership changes.
How has BIIB institutional ownership changed over time?
InsiderSet tracks BIIB institutional holdings across multiple 13F reporting periods, allowing investors to compare institutional holder counts, reported value, and reported shares over time.