Biogen Inc.
US ˙ NasdaqGS ˙ US09062X1037

SecurityBIIB / Biogen Inc.
InstitutionTd Asset Management Inc
Latest Disclosed Ownership127,268 shares
Latest Disclosed Value $ 23,332,042
Td Asset Management Inc reports 5.97% decrease in ownership of BIIB / Biogen Inc.

On May 11, 2026 - Td Asset Management Inc filed a 13F-HR form disclosing ownership of 127,268 shares of Biogen Inc. (US:BIIB) valued at $23,332,042 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 135,352 shares of Biogen Inc.. This represents a change in shares of -5.97% during the quarter. The current value of the position is $24,860,531 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)
2026-05-11 2026-03-31 13F BIOGEN COM 09062X103 127,268 -8,084 -5.97 23,332 -2.05 0.0101
2026-02-10 2025-12-31 13F BIOGEN COM 09062X103 135,352 -25,843 -16.03 23,821 5.49 0.0192
2025-11-10 2025-09-30 13F BIOGEN COM 09062X103 161,195 18,168 12.70 22,580 25.71 0.0183
2025-07-28 2025-06-30 13F BIOGEN COM 09062X103 143,027 -141,349 -49.70 17,963 -53.84 0.0153
2025-05-07 2025-03-31 13F BIOGEN COM 09062X103 284,376 -71,330 -20.05 38,914 -28.46 0.0358
2025-02-11 2024-12-31 13F BIOGEN COM 09062X103 355,706 -15,295 -4.12 54,395 -24.68 0.0481
2024-11-01 2024-09-30 13F BIOGEN COM 09062X103 371,001 -9,787 -2.57 72,223 -18.18 0.0637
2024-08-02 2024-06-30 13F BIOGEN COM 09062X103 380,788 13,552 3.69 88,274 11.48 0.0823
2024-05-08 2024-03-31 13F BIOGEN COM 09062X103 367,236 -22,748 -5.83 79,187 -21.53 0.0737
2024-02-12 2023-12-31 13F BIOGEN COM 09062X103 389,984 108,956 38.77 100,916 39.72 0.0992
2023-10-27 2023-09-30 13F BIOGEN COM 09062X103 281,028 64,844 29.99 72,227 17.29 0.0875
2023-08-09 2023-06-30 13F BIOGEN COM 09062X103 216,184 60,325 38.70 61,580 42.11 0.0701
2023-05-10 2023-03-31 13F BIOGEN COM 09062X103 155,859 -3,860 -2.42 43,333 -2.03 0.0523
2023-02-07 2022-12-31 13F BIOGEN COM 09062X103 159,719 -4,732 -2.88 44,229 1.76 0.0546
2022-11-07 2022-09-30 13F BIOGEN COM 09062X103 164,451 10,013 6.48 43,462 37.99 0.0544
2022-08-04 2022-06-30 13F BIOGEN COM 09062X103 154,438 8,049 5.50 31,496 2.16 0.0365
2022-05-10 2022-03-31 13F BIOGEN COM 09062X103 146,389 -3,095 -2.07 30,830 -14.04 0.0182
2022-05-10 2022-03-31 13F BIOGEN COM 09062X103 146,389 30,830
2022-02-10 2021-12-31 13F BIOGEN COM 09062X103 149,484 2,555 1.74 35,864 -13.74 0.0300
2021-11-09 2021-09-30 13F BIOGEN COM 09062X103 146,929 25,319 20.82 41,579 4.65 0.0432
2021-08-11 2021-06-30 13F BIOGEN COM 09062X103 121,610 -11,425 -8.59 39,733 6.76 0.0403
2021-05-14 2021-03-31 13F BIOGEN COM 09062X103 133,035 2,213 1.69 37,217 16.18 0.0416
2021-02-16 2020-12-31 13F BIOGEN COM 09062X103 130,822 16,821 14.76 32,033 -0.95 0.0389
2020-11-10 2020-09-30 13F BIOGEN COM 09062X103 114,001 24,029 26.71 32,340 34.35 0.0449
2020-08-13 2020-06-30 13F BIOGEN COM 09062X103 89,972 -35,196 -28.12 24,072 -39.21 0.0342
2020-05-15 2020-03-31 13F BIOGEN COM 09062X103 125,168 29,669 31.07 39,601 39.75 0.0670
2020-02-11 2019-12-31 13F BIOGEN COM 09062X103 95,499 11,356 13.50 28,337 44.65 0.0411
2019-11-07 2019-09-30 13F BIOGEN COM 09062X103 84,143 -4,870 -5.47 19,590 -5.89 0.0299
2019-08-01 2019-06-30 13F BIOGEN COM 09062X103 89,013 1,557 1.78 20,817 0.70 0.0312
2019-05-08 2019-03-31 13F BIOGEN COM 09062X103 87,456 -22,018 -20.11 20,673 -37.25 0.0316
2019-02-01 2018-12-31 13F BIOGEN COM 09062X103 109,474 -3,548 -3.14 32,943 -17.50 0.0573
2018-11-01 2018-09-30 13F BIOGEN COM 09062X103 113,022 -6,313 -5.29 39,932 15.29 0.0591
2018-07-31 2018-06-30 13F BIOGEN COM 09062X103 119,335 -37,379 -23.85 34,636 -19.28 0.0528
2018-05-11 2018-03-31 13F BIOGEN COM 09062X103 156,714 -16,996 -9.78 42,911 -22.46 0.0657
2018-02-02 2017-12-31 13F BIOGEN COM 09062X103 173,710 -13,115 -7.02 55,339 -5.40 0.0806
2017-11-09 2017-09-30 13F BIOGEN COM 09062X103 186,825 7,651 4.27 58,499 20.32 0.0877
2017-08-01 2017-06-30 13F BIOGEN COM 09062X103 179,174 -10,761 -5.67 48,621 -6.38 0.0766
2017-05-05 2017-03-31 13F BIOGEN COM 09062X103 189,935 -3,790 -1.96 51,932 -5.47 0.0828
2017-02-08 2016-12-31 13F BIOGEN COM 09062X103 193,725 -10,841 -5.30 54,937 -14.21 0.0926
2016-11-02 2016-09-30 13F BIOGEN COM 09062X103 204,566 7,816 3.97 64,035 34.59 0.1108
2016-08-04 2016-06-30 13F BIOGEN COM 09062X103 196,750 -8,458 -4.12 47,578 -10.94 0.0863
2016-05-05 2016-03-31 13F BIOGEN COM 09062X103 205,208 -17,561 -7.88 53,420 -21.72 0.0999
2016-02-04 2015-12-31 13F BIOGEN COM 09062X103 222,769 12,149 5.77 68,245 11.04 0.1354
2015-11-12 2015-09-30 13F BIOGEN COM 09062X103 210,620 -50,400 -19.31 61,461 -41.71 0.1210
2015-08-11 2015-06-30 13F BIOGEN COM 09062X103 261,020 -9,244 -3.42 105,436 -7.61 0.1883
2015-04-28 2015-03-31 13F BIOGEN COM 09062X103 270,264 270,264 0.00 114,116 0.2060
2015-01-30 2014-12-31 13F BIOGEN IDEC COM 09062X103 0 -292,536 -100.00 0 -100.00
2014-11-06 2014-09-30 13F BIOGEN IDEC COM 09062X103 292,536 21,797 8.05 96,774 13.36 0.1669
2014-08-12 2014-06-30 13F BIOGEN IDEC COM 09062X103 270,739 -8,400 -3.01 85,367 -0.02 0.1454
2014-05-09 2014-03-31 13F BIOGEN IDEC COM 09062X103 279,139 9,474 3.51 85,380 13.18 0.1553
2014-02-07 2013-12-31 13F BIOGEN IDEC COM 09062X103 269,665 9,500 3.65 75,439 20.44 0.1409
2013-11-08 2013-09-30 13F BIOGEN IDEC COM 09062X103 260,165 -4,800 -1.81 62,637 9.85 0.1244
2013-07-24 2013-06-30 13F BIOGEN IDEC COM 09062X103 264,965 264,965 57,020 0.1223
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.