Biogen Inc.
US ˙ NasdaqGS ˙ US09062X1037

SecurityBIIB / Biogen Inc.
InstitutionFranklin Resources Inc
Latest Disclosed Ownership144,448 shares
Latest Disclosed Value $ 26,481,653
Franklin Resources Inc reports 2.17% increase in ownership of BIIB / Biogen Inc.

On May 13, 2026 - Franklin Resources Inc filed a 13F-HR form disclosing ownership of 144,448 shares of Biogen Inc. (US:BIIB) valued at $26,481,652 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 11, 2026 disclosing 141,374 shares of Biogen Inc.. This represents a change in shares of 2.17% during the quarter. The current value of the position is $28,306,030 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-13 2026-03-31 13F BIOGEN COM 09062X103 144,448 3,074 2.17 26,482 6.43 0.0065
2026-02-11 2025-12-31 13F BIOGEN COM 09062X103 141,374 -87,782 -38.31 24,880 -22.49 0.0061
2025-11-13 2025-09-30 13F BIOGEN COM 09062X103 229,156 146 0.06 32,100 11.61 0.0080
2025-08-12 2025-06-30 13F BIOGEN COM 09062X103 229,010 -359,107 -61.06 28,761 -64.26 0.0076
2025-05-13 2025-03-31 13F BIOGEN COM 09062X103 588,117 193,726 49.12 80,478 33.44 0.0232
2025-02-12 2024-12-31 13F BIOGEN COM 09062X103 394,391 19,644 5.24 60,310 -15.99 0.0167
2024-11-27 2024-09-30 13F/A-1 BIOGEN COM 09062X103 374,747 -13,723 -3.53 71,787 -20.29 0.0202
2024-11-12 2024-09-30 13F BIOGEN COM 09062X103 374,747 -13,723 71,787 0.0035
2024-08-14 2024-06-30 13F BIOGEN COM 09062X103 388,470 2,887 0.75 90,055 8.31 0.0277
2024-05-13 2024-03-31 13F BIOGEN COM 09062X103 385,583 -112,766 -22.63 83,143 -35.53 0.0263
2024-02-09 2023-12-31 13F BIOGEN COM 09062X103 498,349 -130,185 -20.71 128,958 -20.17 0.0603
2023-11-13 2023-09-30 13F BIOGEN COM 09062X103 628,534 185,742 41.95 161,540 28.07 0.0821
2023-08-11 2023-06-30 13F BIOGEN COM 09062X103 442,792 17,106 4.02 126,129 6.57 0.0600
2023-05-12 2023-03-31 13F BIOGEN COM 09062X103 425,686 3,602 0.85 118,353 1.26 0.0594
2023-02-10 2022-12-31 13F BIOGEN COM 09062X103 422,084 12,842 3.14 116,884 6.97 0.0607
2022-11-14 2022-09-30 13F BIOGEN COM 09062X103 409,242 -3,607 -0.87 109,267 29.78 0.0595
2022-08-11 2022-06-30 13F BIOGEN COM 09062X103 412,849 -2,533 -0.61 84,197 -3.75 0.0418
2022-05-13 2022-03-31 13F BIOGEN COM 09062X103 415,382 -46,100 -9.99 87,480 -20.99 0.0350
2022-02-11 2021-12-31 13F BIOGEN COM 09062X103 461,482 -24,813 -5.10 110,719 -19.54 0.0399
2021-11-12 2021-09-30 13F BIOGEN COM 09062X103 486,295 14,995 3.18 137,615 -15.68 0.0518
2021-08-13 2021-06-30 13F BIOGEN COM 09062X103 471,300 -58,979 -11.12 163,197 10.01 0.0624
2021-05-13 2021-03-31 13F BIOGEN COM 09062X103 530,279 56,427 11.91 148,347 27.85 0.0604
2021-02-10 2020-12-31 13F BIOGEN COM 09062X103 473,852 -120,445 -20.27 116,028 -31.18 0.0491
2020-11-12 2020-09-30 13F BIOGEN COM 09062X103 594,297 17,024 2.95 168,589 4.00 0.0816
2020-08-13 2020-06-30 13F BIOGEN COM 09062X103 577,273 -68,799 -10.65 162,103 -20.69 0.0835
2020-05-13 2020-03-31 13F BIOGEN COM 09062X103 646,072 56,942 9.67 204,403 16.93 0.1364
2020-03-11 2019-12-31 13F/A-1 BIOGEN COM 09062X103 589,130 16,529 2.89 174,812 31.13 0.0918
2020-02-12 2019-12-31 13F BIOGEN COM 09062X103 589,130 16,529 174,812 22,081.1489
2019-11-14 2019-09-30 13F BIOGEN COM 09062X103 572,601 -533,621 -48.24 133,315 -48.47 0.0724
2019-08-14 2019-06-30 13F BIOGEN COM 09062X103 1,106,222 29,269 2.72 258,711 1.63 0.1376
2019-05-15 2019-03-31 13F/A-1 BIOGEN COM 09062X103 1,076,953 -115,763 -9.71 254,571 -29.07 0.1363
2019-05-14 2019-03-31 13F BIOGEN COM 09062X103 1,076,953 -115,763 254,571
2019-02-12 2018-12-31 13F BIOGEN COM 09062X103 1,192,716 40,090 3.48 358,912 -11.87 0.2166
2018-11-13 2018-09-30 13F BIOGEN COM 09062X103 1,152,626 3,642 0.32 407,235 22.12 0.2027
2018-08-14 2018-06-30 13F BIOGEN COM 09062X103 1,148,984 6,288 0.55 333,481 6.58 0.1711
2018-05-10 2018-03-31 13F BIOGEN COM 09062X103 1,142,696 -295,324 -20.54 312,894 -31.70 0.1586
2018-02-14 2017-12-31 13F BIOGEN COM 09062X103 1,438,020 45,975 3.30 458,114 5.10 0.2198
2017-11-13 2017-09-30 13F BIOGEN COM 09062X103 1,392,045 -24,192 -1.71 435,870 13.42 0.2137
2017-08-10 2017-06-30 13F BIOGEN COM 09062X103 1,416,237 -346,987 -19.68 384,309 -20.28 0.1916
2017-05-12 2017-03-31 13F BIOGEN COM 09062X103 1,763,224 -25,695 -1.44 482,075 -4.98 0.2447
2017-02-14 2016-12-31 13F BIOGEN COM 09062X103 1,788,919 -111,161 -5.85 507,322 -14.70 0.2626
2016-11-14 2016-09-30 13F BIOGEN COM 09062X103 1,900,080 -65,747 -3.34 594,733 25.11 0.3110
2016-08-11 2016-06-30 13F BIOGEN COM 09062X103 1,965,827 -101,492 -4.91 475,375 -11.67 0.2557
2016-05-10 2016-03-31 13F BIOGEN COM 09062X103 2,067,319 -48,255 -2.28 538,170 -16.96 0.2857
2016-04-27 2015-12-31 13F/A-1 BIOGEN COM 09062X103 2,115,574 -259,337 -10.92 648,119 -6.48 0.3281
2016-02-12 2015-12-31 13F BIOGEN COM 09062X103 2,115,574 648,119
2015-11-10 2015-09-30 13F BIOGEN COM 09062X103 2,374,911 148,469 6.67 693,034 -22.94 0.3423
2015-08-12 2015-06-30 13F BIOGEN COM 09062X103 2,226,442 -67,165 -2.93 899,350 -7.13 0.4082
2015-05-14 2015-03-31 13F BIOGEN COM 09062X103 2,293,607 167,123 7.86 968,447 34.16 0.4391
2015-02-10 2014-12-31 13F BIOGEN IDEC COM 09062X103 2,126,484 102,385 5.06 721,838 7.80 0.3274
2014-11-12 2014-09-30 13F BIOGEN IDEC COM 09062X103 2,024,099 -257,199 -11.27 669,587 -6.91 0.3054
2014-08-12 2014-06-30 13F BIOGEN IDEC COM 09062X103 2,281,298 -1,155 -0.05 719,308 3.03 0.3169
2014-05-13 2014-03-31 13F BIOGEN IDEC COM 09062X103 2,282,453 428,125 23.09 698,132 34.58 0.3297
2014-02-12 2013-12-31 13F BIOGEN IDEC COM 09062X103 1,854,328 175,987 10.49 518,747 28.38 0.2536
2013-11-14 2013-09-30 13F BIOGEN IDEC COM 09062X103 1,678,341 71,092 4.42 404,076 16.83 0.2151
2013-08-09 2013-06-30 13F BIOGEN IDEC COM 09062X103 1,607,249 1,607,249 345,881 0.1975
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.