| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| PRIMECAP MANAGEMENT CO/CA/ | 10% | $2,094,853,956 | 14,954,697 | PRIMECAP MANAGEMENT CO/CA/ | 30 Sep 2025 | |||
| BlackRock, Inc. | 8.5% | $1,502,927,856 | 12,506,681 | BlackRock, Inc. | 31 Mar 2025 | |||
| FMR LLC | 6.4% | $1,656,604,787 | 9,413,062 | FMR LLC | 31 Dec 2025 | |||
| STATE STREET CORP | 5% | $1,025,549,213 | 7,321,168 | STATE STREET CORPORATION | 30 Sep 2025 |
As of 31 Dec 2025, 965 institutional investors reported holding 137,275,246 shares of BIOGEN INC. - COMMON STOCK (BIIB). This represents 93% of the company’s total 147,079,094 outstanding shares.
The largest institutional shareholders of BIOGEN INC. - COMMON STOCK (BIIB) together control 67% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| VANGUARD GROUP INC | 12% | 17,447,092 | +0.91% | 0.04% | $3,070,513,721 |
| BlackRock, Inc. | 10% | 14,811,370 | +0.32% | 0.04% | $2,606,652,919 |
| PRIMECAP MANAGEMENT CO/CA/ | 10% | 14,757,997 | -1.3% | 2% | $2,597,259,895 |
| FMR LLC | 6.4% | 9,425,863 | +632% | 0.08% | $1,658,857,459 |
| STATE STREET CORP | 4.9% | 7,159,020 | -2.2% | 0.04% | $1,259,915,930 |
| GEODE CAPITAL MANAGEMENT, LLC | 2.9% | 4,199,399 | +3.2% | 0.05% | $736,434,804 |
| WELLINGTON MANAGEMENT GROUP LLP | 2.4% | 3,551,269 | -16% | 0.11% | $624,987,832 |
| Point72 Asset Management, L.P. | 1.9% | 2,813,192 | -27% | 0.78% | $495,093,660 |
| NORGES BANK | 1.8% | 2,638,834 | 0.05% | $464,408,396 | |
| MORGAN STANLEY | 1.6% | 2,325,013 | +3.3% | 0.02% | $409,179,635 |
| JPMORGAN CHASE & CO | 1.3% | 1,857,262 | +46% | 0.02% | $326,859,629 |
| Boston Partners | 1.2% | 1,720,595 | 0.31% | $302,815,433 | |
| Invesco Ltd. | 1.1% | 1,655,441 | -32% | 0.04% | $291,341,046 |
| AQR CAPITAL MANAGEMENT LLC | 1% | 1,528,616 | -14% | 0.14% | $269,021,112 |
| Legal & General Group Plc | 0.99% | 1,459,597 | -8.4% | 0.06% | $256,874,480 |
| NORTHERN TRUST CORP | 0.98% | 1,446,126 | -3.5% | 0.03% | $254,503,714 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC | 0.95% | 1,391,370 | -3.3% | 0.05% | $244,867,205 |
| BARCLAYS PLC | 0.89% | 1,305,007 | -4% | 0.09% | $229,668,181 |
| T. Rowe Price Investment Management, Inc. | 0.8% | 1,170,907 | +9.7% | 0.13% | $206,068,000 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 0.78% | 1,143,902 | +1.8% | 0.03% | $201,315,313 |
| BANK OF AMERICA CORP /DE/ | 0.77% | 1,128,845 | -7.5% | 0.01% | $198,665,432 |
| MILLENNIUM MANAGEMENT LLC | 0.77% | 1,125,586 | +1.3% | 0.14% | $198,091,880 |
| GOLDMAN SACHS GROUP INC | 0.75% | 1,099,098 | +3.3% | 0.03% | $193,430,233 |
| VAN ECK ASSOCIATES CORP | 0.72% | 1,065,616 | -0.12% | 0.15% | $187,538,000 |
| Alyeska Investment Group, L.P. | 0.7% | 1,024,268 | +21% | 0.51% | $180,260,925 |
| Period | Reported Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2025 Q4 | 137,275,246 | $24,155,390,401 | +$1,329,350,452 | $175.99 | 965 |
| 2025 Q3 | 130,394,386 | $18,268,725,836 | +$165,528,624 | $140.08 | 891 |
| 2025 Q2 | 129,287,238 | $16,238,624,437 | +$284,309,412 | $125.59 | 856 |
| 2025 Q1 | 127,028,107 | $17,371,280,984 | -$578,239,538 | $136.84 | 865 |
| 2024 Q4 | 131,405,263 | $20,085,982,511 | +$272,768,825 | $152.92 | 861 |
| 2024 Q3 | 128,615,457 | $24,913,936,182 | -$143,640,766 | $193.84 | 903 |
| 2024 Q2 | 128,193,288 | $29,710,612,652 | -$84,741,446 | $231.82 | 933 |
| 2024 Q1 | 128,518,741 | $27,691,040,526 | +$55,007,555 | $215.63 | 932 |
| 2023 Q4 | 127,982,276 | $33,111,816,739 | +$901,376,761 | $258.77 | 993 |
| 2023 Q3 | 124,470,870 | $31,994,071,856 | -$470,206,356 | $257.01 | 954 |
| 2023 Q2 | 126,306,466 | $35,966,219,806 | +$277,366,431 | $284.85 | 994 |
| 2023 Q1 | 125,053,711 | $34,758,696,486 | +$300,589,329 | $278.03 | 987 |
| 2022 Q4 | 124,528,759 | $34,492,440,417 | +$242,887,240 | $276.92 | 1,018 |
| 2022 Q3 | 123,323,995 | $32,917,825,335 | +$384,787,916 | $267.00 | 966 |
| 2022 Q2 | 121,790,135 | $24,840,540,438 | -$152,960,663 | $203.94 | 911 |
| 2022 Q1 | 122,616,063 | $25,827,895,030 | -$220,078,557 | $210.60 | 941 |
| 2021 Q4 | 123,500,078 | $29,628,123,955 | -$101,746,917 | $239.92 | 996 |
| 2021 Q3 | 123,461,166 | $34,947,282,206 | -$614,669,326 | $282.99 | 1,026 |
| 2021 Q2 | 125,522,812 | $43,460,004,330 | -$566,581,701 | $346.27 | 1,091 |
| 2021 Q1 | 127,388,312 | $35,598,424,357 | -$380,775,241 | $279.75 | 1,079 |
| 2020 Q4 | 128,905,111 | $31,559,604,046 | -$521,085,738 | $244.86 | 1,047 |
| 2020 Q3 | 130,781,613 | $37,077,214,726 | -$1,220,436,591 | $283.68 | 1,036 |
| 2020 Q2 | 134,944,833 | $36,078,566,447 | -$2,622,299,974 | $267.55 | 1,048 |
| 2020 Q1 | 144,371,093 | $45,633,042,157 | -$2,072,462,238 | $316.38 | 1,090 |
| 2019 Q4 | 150,927,624 | $44,753,934,396 | -$2,257,146,159 | $296.73 | 1,090 |
| 2019 Q3 | 159,069,579 | $37,018,304,080 | -$348,502,414 | $232.82 | 972 |
| 2019 Q2 | 160,395,186 | $37,502,672,698 | -$2,138,732,747 | $233.87 | 1,002 |
| 2019 Q1 | 171,326,218 | $40,468,172,998 | -$1,011,646,914 | $236.38 | 1,071 |
| 2018 Q4 | 175,003,235 | $52,619,725,529 | -$839,325,018 | $300.92 | 1,135 |
| 2018 Q3 | 177,270,767 | $62,594,382,952 | -$269,008,690 | $353.31 | 1,140 |
| 2018 Q2 | 178,340,992 | $51,731,992,582 | -$2,444,250,744 | $290.24 | 1,087 |
| 2018 Q1 | 186,913,555 | $51,164,896,552 | -$488,678,007 | $273.82 | 1,096 |
| 2017 Q4 | 188,568,529 | $60,044,982,772 | +$9,889,834 | $318.57 | 1,120 |
| 2017 Q3 | 188,385,830 | $58,970,231,587 | +$472,002,826 | $313.12 | 1,011 |
| 2017 Q2 | 187,380,108 | $50,837,222,531 | +$288,984,209 | $271.36 | 991 |
| 2017 Q1 | 188,211,491 | $51,456,575,196 | +$4,118,247,453 | $273.42 | 1,016 |
| 2016 Q4 | 189,394,911 | $53,679,916,033 | -$1,015,070,941 | $283.58 | 1,021 |
| 2016 Q3 | 191,778,014 | $60,010,956,983 | +$480,242,801 | $313.03 | 1,007 |
| 2016 Q2 | 190,842,498 | $46,263,524,155 | -$112,555,041 | $241.82 | 957 |
| 2016 Q1 | 190,858,170 | $49,747,381,290 | -$388,687,634 | $260.32 | 938 |
| 2015 Q4 | 192,339,308 | $59,013,396,053 | -$2,589,949,247 | $306.35 | 965 |
| 2015 Q3 | 200,266,975 | $58,440,502,406 | -$3,822,036,876 | $291.81 | 914 |
| 2015 Q2 | 211,110,431 | $85,274,602,341 | -$1,015,846,158 | $403.94 | 961 |
| 2015 Q1 | 213,693,704 | $90,176,303,862 | +$321,462,904 | $422.24 | 961 |
| 2014 Q4 | 213,378,369 | $72,452,156,965 | -$502,527,627 | $339.45 | 877 |
| 2014 Q3 | 214,442,358 | $70,936,086,109 | -$177,791,858 | $330.81 | 811 |
| 2014 Q2 | 214,744,481 | $67,717,564,176 | +$911,109,846 | $315.31 | 777 |
| 2014 Q1 | 212,004,121 | $64,813,130,089 | -$390,248,896 | $305.87 | 767 |