Biogen Inc.
MX ˙ BMV ˙ US09062X1037
SecurityMX:BIIB / Biogen Inc.
InstitutionSector Gamma As
Latest Disclosed Ownership90,096 shares
Latest Disclosed Value $ 16,517,300
Sector Gamma As reports 5.41% increase in ownership of BIIB / Biogen Inc.

On May 7, 2026 - Sector Gamma As filed a 13F-HR form disclosing ownership of 90,096 shares of Biogen Inc. (MX:BIIB) valued at $16,517,300 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 85,475 shares of Biogen Inc.. This represents a change in shares of 5.41% during the quarter.

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)
2026-05-07 2026-03-31 13F BIOGEN COM 09062X103 90,096 4,621 5.41 16,517 9.81 3.9003
2026-02-12 2025-12-31 13F BIOGEN COM 09062X103 85,475 10,000 13.25 15,043 42.28 3.4288
2025-10-31 2025-09-30 13F BIOGEN COM 09062X103 75,475 24,836 49.05 10,573 66.25 2.6214
2025-07-31 2025-06-30 13F BIOGEN COM 09062X103 50,639 32,000 171.68 6,360 149.37 2.0787
2025-05-13 2025-03-31 13F BIOGEN COM 09062X103 18,639 -10,361 -35.73 2,551 -42.49 0.8170
2025-02-11 2024-12-31 13F BIOGEN COM 09062X103 29,000 -6,166 -17.53 4,435 -34.95 1.5246
2024-11-13 2024-09-30 13F BIOGEN COM 09062X103 35,166 -8,819 -20.05 6,817 -33.15 2.0683
2024-08-09 2024-06-30 13F BIOGEN COM 09062X103 43,985 -15,713 -26.32 10,197 -20.79 3.8093
2024-05-08 2024-03-31 13F BIOGEN COM 09062X103 59,698 -42,536 -41.61 12,873 -51.34 3.6282
2024-02-05 2023-12-31 13F BIOGEN COM 09062X103 102,234 -2,052 -1.97 26,455 -1.29 6.4191
2023-11-06 2023-09-30 13F BIOGEN COM 09062X103 104,286 8,529 8.91 26,803 -1.74 6.8501
2023-08-09 2023-06-30 13F BIOGEN COM 09062X103 95,757 7,921 9.02 27,276 11.69 6.1030
2023-05-12 2023-03-31 13F BIOGEN COM 09062X103 87,836 17,797 25.41 24,421 25.91 5.9205
2023-02-08 2022-12-31 13F/A-1 BIOGEN COM 09062X103 70,039 -40,191 -36.46 19,395 -34.10 4.4342
2023-02-07 2022-12-31 13F BIOGEN COM 09062X103 70,039 -40,191 19 4.4341
2022-11-09 2022-09-30 13F BIOGEN COM 09062X103 110,230 17,733 19.17 29,431 56.02 7.5848
2022-08-05 2022-06-30 13F BIOGEN COM 09062X103 92,497 10,552 12.88 18,864 9.31 4.2206
2022-05-06 2022-03-31 13F BIOGEN COM 09062X103 81,945 15,346 23.04 17,258 8.01 3.7500
2022-02-08 2021-12-31 13F BIOGEN COM 09062X103 66,599 -16,720 -20.07 15,978 -32.23 3.7558
2021-10-29 2021-09-30 13F BIOGEN COM 09062X103 83,319 10,276 14.07 23,578 -6.78 4.7035
2021-08-04 2021-06-30 13F BIOGEN COM 09062X103 73,043 23,783 48.28 25,293 83.55 4.4797
2021-05-10 2021-03-31 13F BIOGEN COM 09062X103 49,260 -16,325 -24.89 13,780 -14.19 2.5238
2021-02-10 2020-12-31 13F BIOGEN COM 09062X103 65,585 -1,758 -2.61 16,059 -15.94 3.0560
2020-11-09 2020-09-30 13F BIOGEN COM 09062X103 67,343 3,123 4.86 19,104 11.19 4.3482
2020-08-07 2020-06-30 13F BIOGEN COM 09062X103 64,220 -10,900 -14.51 17,182 -27.70 3.5468
2020-05-11 2020-03-31 13F BIOGEN COM 09062X103 75,120 -27,099 -26.51 23,766 -21.64 5.0672
2020-02-12 2019-12-31 13F BIOGEN COM 09062X103 102,219 49,793 94.98 30,331 148.49 4.8577
2019-11-05 2019-09-30 13F BIOGEN COM 09062X103 52,426 -62,700 -54.46 12,206 -54.67 2.0624
2019-07-31 2019-06-30 13F BIOGEN COM 09062X103 115,126 -35,074 -23.35 26,925 -24.16 4.3279
2019-05-13 2019-03-31 13F BIOGEN COM 09062X103 150,200 117,100 353.78 35,504 256.47 5.6939
2019-02-12 2018-12-31 13F BIOGEN COM 09062X103 33,100 -2,900 -8.06 9,960 -21.69 1.6747
2018-11-15 2018-09-30 13F/A-1 BIOGEN COM 09062X103 36,000 36,000 12,719 1.9942
2018-11-08 2018-09-30 13F BIOGEN COM 09062X103 19,979 19,979 7,059
2018-05-09 2018-03-31 13F BIOGEN COM 09062X103 0 -65,800 -100.00 0 -100.00
2018-02-12 2017-12-31 13F BIOGEN COM 09062X103 65,800 -18,200 -21.67 20,962 -20.30 3.5234
2017-11-07 2017-09-30 13F BIOGEN IDEC COM 09062X103 84,000 26,200 45.33 26,302 67.69 4.0090
2017-08-14 2017-06-30 13F BIOGEN IDEC COM 09062X103 57,800 57,800 15,685 2.2804
2017-02-14 2016-12-31 13F BIOGEN IDEC COM 09062X103 0 -71,400 -100.00 0 -100.00
2016-11-08 2016-09-30 13F BIOGEN IDEC COM 09062X103 71,400 -25,290 -26.16 21,107 -9.73 3.9537
2016-08-11 2016-06-30 13F BIOGEN IDEC COM 09062X103 96,690 14,780 18.04 23,382 9.66 4.7318
2016-05-27 2016-03-31 13F BIOGEN IDEC COM 09062X103 81,910 6,610 8.78 21,323 -7.56 4.4667
2016-02-12 2015-12-31 13F BIOGEN IDEC COM 09062X103 75,300 46,700 163.29 23,068 176.40 5.9269
2015-11-16 2015-09-30 13F BIOGEN IDEC COM 09062X103 28,600 8,600 43.00 8,346 49.28 2.2595
2014-02-14 2013-12-31 13F BIOGEN IDEC COM 09062X103 20,000 20,000 5,591 1.5085
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.