BIOGEN INC (BIIB) Institutional Shareholders
BIOGEN INC (BIIB) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026. The institutional investors covered on this page collectively reported approximately $29.95B in BIIB holdings during the latest filing period.
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 $3.82B, representing an estimated loss of -2.88% 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
1,009
Total Reported Value
$29.95B
Largest Holder
Fmr Llc
Largest Position
$3.94B
Insider Transactions (90d)
12
Latest Filing Quarter
Q2 2026
New Institutional Positions
62
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 | $3,822,523,259 | -$113,493,293 | -2.88% | |
| Blackrock, Inc. | 0.05% | 15,985,736 | $3,453,877,982 | $3,354,286,985 | -$99,590,997 | -2.88% | |
| Primecap Management Co/Ca/ | 1.94% | 15,154,606 | $3,274,304,389 | $3,179,890,977 | -$94,413,412 | -2.88% | |
| Vanguard Capital Management Llc | 0.04% | 9,651,117 | $2,085,220,339 | $2,025,093,880 | -$60,126,459 | -2.88% | |
| State Street Corp | 0.05% | 7,344,327 | $1,586,815,292 | $1,541,060,134 | -$45,755,158 | -2.88% | |
| Vanguard Portfolio Management Llc | 0.06% | 6,604,936 | $1,427,062,472 | $1,385,913,721 | -$41,148,751 | -2.88% | |
| Geode Capital Management, Llc | 0.05% | 4,449,295 | $957,935,835 | $933,595,570 | -$24,340,265 | -2.54% | |
| Wellington Management Group Llp | 0.12% | 3,117,469 | $673,560,352 | $654,138,520 | -$19,421,832 | -2.88% | |
| Norges Bank | 0.06% | 2,580,033 | $557,441,930 | $541,368,324 | -$16,073,606 | -2.88% | |
| Morgan Stanley | 0.03% | 2,411,271 | $520,979,947 | $505,956,994 | -$15,022,953 | -2.88% | |
| Aqr Capital Management Llc | 0.15% | 1,936,859 | $416,928,075 | $406,411,124 | -$10,516,951 | -2.52% | |
| Jpmorgan Chase & Co | 0.02% | 1,823,140 | $394,947,245 | $382,549,466 | -$12,397,779 | -3.14% | |
| Invesco Ltd. | 0.03% | 1,803,944 | $389,760,120 | $378,521,570 | -$11,238,550 | -2.88% | |
| Amundi | 0.08% | 1,516,831 | $327,726,507 | $318,276,649 | -$9,449,858 | -2.88% | |
| Legal & General Group Plc | 0.07% | 1,493,289 | $322,640,021 | $313,336,831 | -$9,303,190 | -2.88% | |
| Northern Trust Corp | 0.04% | 1,429,490 | $308,855,610 | $299,949,887 | -$8,905,723 | -2.88% | |
| Boston Partners | 0.24% | 1,263,429 | $272,849,469 | $265,105,307 | -$7,744,162 | -2.84% | |
| Goldman Sachs Group Inc | 0.03% | 1,230,390 | $265,838,021 | $258,172,734 | -$7,665,287 | -2.88% | |
| Ubs Am, A Distinct Business Unit Of Ubs Asset Management Americas Llc | 0.05% | 1,377,568 | $252,549,543 | $289,055,093 | +$36,505,550 | +14.45% | |
| Dimensional Fund Advisors Lp | 0.04% | 1,148,568 | $248,165,892 | $241,004,023 | -$7,161,869 | -2.89% | |
| Charles Schwab Investment Management Inc | 0.03% | 1,117,663 | $241,482,267 | $234,519,227 | -$6,963,040 | -2.88% | |
| Sixth Street Partners Management Company, L.P. | 0.03% | 1,117,663 | $241,482,267 | $234,519,227 | -$6,963,040 | -2.88% | |
| Bank Of America Corp | 0.02% | 1,116,228 | $241,172,222 | $234,218,121 | -$6,954,101 | -2.88% | |
| Ubs Group Ag | 0.04% | 1,030,150 | $222,574,209 | $216,156,375 | -$6,417,835 | -2.88% | |
| Alyeska Investment Group, L.P. | 0.52% | 932,374 | $201,448,726 | $195,640,036 | -$5,808,690 | -2.88% | |
| Deutsche Bank Ag\ | 0.06% | 894,035 | $193,165,202 | $187,595,364 | -$5,569,838 | -2.88% | |
| Pictet Asset Management Holding Sa | 0.18% | 851,819 | $184,144,886 | $178,737,181 | -$5,407,705 | -2.94% | |
| Vanguard Fiduciary Trust Co | 0.04% | 829,318 | $179,182,447 | $174,015,796 | -$5,166,651 | -2.88% | |
| Robeco Institutional Asset Management B.V. | 0.21% | 791,092 | $170,923,341 | $165,994,834 | -$4,928,507 | -2.88% | |
| Fred Alger Management, Llc | 0.57% | 788,307 | $170,321,610 | $165,410,458 | -$4,911,152 | -2.88% | |
| Bank Of New York Mellon Corp | 0.03% | 773,619 | $167,148,200 | $162,328,475 | -$4,819,725 | -2.88% | |
| Massachusetts Financial Services Co | 0.05% | 744,892 | $163,127,433 | $156,300,688 | -$6,826,745 | -4.18% | |
| Citigroup Inc | 0.07% | 734,517 | $158,699,743 | $154,123,702 | -$4,576,041 | -2.88% | |
| Royal Bank Of Canada | 0.03% | 708,562 | $153,093,000 | $148,677,564 | -$4,415,436 | -2.88% | |
| Employees Provident Fund Board | 0.87% | 704,196 | $152,148,588 | $147,761,447 | -$4,387,141 | -2.88% | |
| First Trust Advisors Lp | 0.09% | 682,021 | $147,357,277 | $143,108,466 | -$4,248,811 | -2.88% | |
| Australiansuper Pty Ltd | 0.63% | 672,723 | $145,348,531 | $141,157,467 | -$4,191,064 | -2.88% | |
| Artemis Investment Management Llp | 1.10% | 570,974 | $123,364,642 | $119,807,474 | -$3,557,168 | -2.88% | |
| Zurcher Kantonalbank (Zurich Cantonalbank) | 0.22% | 540,001 | $116,672,616 | $113,308,410 | -$3,364,206 | -2.88% | |
| Hsbc Holdings Plc | 0.05% | 527,866 | $113,972,342 | $110,762,123 | -$3,210,219 | -2.82% | |
| Caisse De Depot Et Placement Du Quebec | 0.16% | 510,194 | $110,232,516 | $107,054,007 | -$3,178,509 | -2.88% | |
| Citadel Advisors Llc | 0.05% | 418,356 | $90,389,997 | $87,783,639 | -$2,606,358 | -2.88% | |
| Swiss National Bank | 0.05% | 413,900 | $89,427,234 | $86,848,637 | -$2,578,597 | -2.88% | |
| National Pension Service | 0.06% | 406,064 | $87,734,188 | $85,204,409 | -$2,529,779 | -2.88% | |
| Bnp Paribas Financial Markets | 0.04% | 387,542 | $83,732,325 | $81,317,938 | -$2,414,387 | -2.88% | |
| Candriam S.C.A. | 0.37% | 384,326 | $82,957,583 | $80,643,125 | -$2,314,458 | -2.79% | |
| Mitsubishi Ufj Asset Management Co., Ltd. | 0.04% | 358,823 | $77,527,297 | $75,291,830 | -$2,235,467 | -2.88% | |
| Sumitomo Mitsui Trust Group, Inc. | 0.04% | 346,617 | $74,890,069 | $72,730,645 | -$2,159,424 | -2.88% | |
| Victory Capital Management Inc | 0.04% | 343,419 | $74,199,109 | $72,059,609 | -$2,139,500 | -2.88% | |
| Fil Ltd | 0.05% | 342,623 | $74,027,126 | $71,892,584 | -$2,134,542 | -2.88% |
Frequently asked questions about BIIB
Who owns the most BIIB stock?
The largest holders of BIIB are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for BIOGEN INC (BIIB).
Is BIIB widely held by superinvestors?
Many widely followed stocks like BIIB appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly BIIB is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.