Biogen Inc.
US ˙ NasdaqGS ˙ US09062X1037

SecurityBIIB / Biogen Inc.
InstitutionGrimes & Company, Inc.
Latest Disclosed Ownership34,684 shares
Latest Disclosed Value $ 6,358,611
Grimes & Company, Inc. reports 2.48% increase in ownership of BIIB / Biogen Inc.

On April 21, 2026 - Grimes & Company, Inc. filed a 13F-HR form disclosing ownership of 34,684 shares of Biogen Inc. (US:BIIB) valued at $6,358,618 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 3, 2026 disclosing 33,844 shares of Biogen Inc.. This represents a change in shares of 2.48% during the quarter. The current value of the position is $6,796,677 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)
2026-04-21 2026-03-31 13F BIOGEN COM 09062X103 34,684 840 2.48 6,359 6.75 0.1760
2026-02-03 2025-12-31 13F BIOGEN COM 09062X103 33,844 -1,453 -4.12 5,956 20.47 0.1423
2025-10-27 2025-09-30 13F BIOGEN COM 09062X103 35,297 -5,727 -13.96 4,944 -4.04 0.1221
2025-07-22 2025-06-30 13F BIOGEN COM 09062X103 41,024 -18,310 -30.86 5,152 -36.54 0.1402
2025-04-17 2025-03-31 13F BIOGEN COM 09062X103 59,334 33,721 131.66 8,119 107.33 0.2510
2025-01-21 2024-12-31 13F BIOGEN COM 09062X103 25,613 -21,854 -46.04 3,917 -57.44 0.1128
2024-10-22 2024-09-30 13F BIOGEN COM 09062X103 47,467 -273 -0.57 9,201 -16.86 0.2490
2024-07-22 2024-06-30 13F BIOGEN COM 09062X103 47,740 852 1.82 11,067 9.47 0.3312
2024-04-17 2024-03-31 13F BIOGEN COM 09062X103 46,888 1,689 3.74 10,111 -13.56 0.3108
2024-01-24 2023-12-31 13F BIOGEN COM 09062X103 45,199 629 1.41 11,696 2.10 0.3872
2023-10-19 2023-09-30 13F BIOGEN COM 09062X103 44,570 486 1.10 11,455 -8.78 0.4430
2023-07-19 2023-06-30 13F BIOGEN COM 09062X103 44,084 -404 -0.91 12,557 1.53 0.4453
2023-04-20 2023-03-31 13F BIOGEN COM 09062X103 44,488 -1,547 -3.36 12,369 -2.98 0.5069
2023-01-25 2022-12-31 13F BIOGEN COM 09062X103 46,035 -686 -1.47 12,748 2.19 0.5381
2022-10-28 2022-09-30 13F BIOGEN COM 09062X103 46,721 595 1.29 12,475 32.61 0.6510
2022-07-22 2022-06-30 13F BIOGEN COM 09062X103 46,126 938 2.08 9,407 -1.16 0.4743
2022-05-06 2022-03-31 13F BIOGEN COM 09062X103 45,188 3,659 8.81 9,517 -4.49 0.4446
2022-02-01 2021-12-31 13F BIOGEN COM 09062X103 41,529 -312 -0.75 9,964 -15.85 0.4561
2021-11-08 2021-09-30 13F BIOGEN COM 09062X103 41,841 -13 -0.03 11,841 -18.30 0.5152
2021-08-04 2021-06-30 13F BIOGEN COM 09062X103 41,854 -197 -0.47 14,493 23.20 0.6288
2021-05-12 2021-03-31 13F BIOGEN COM 09062X103 42,051 3,341 8.63 11,764 24.11 0.5657
2021-02-02 2020-12-31 13F Biogen IDEC COM 09062X103 38,710 3,010 8.43 9,479 -6.40 0.4925
2020-11-12 2020-09-30 13F Biogen IDEC COM 09062X103 35,700 3,506 10.89 10,127 17.56 0.6477
2020-07-31 2020-06-30 13F Biogen IDEC COM 09062X103 32,194 -195 -0.60 8,614 -15.94 0.5986
2020-05-05 2020-03-31 13F Biogen IDEC COM 09062X103 32,389 -328 -1.00 10,247 5.55 0.9353
2020-02-05 2019-12-31 13F Biogen IDEC COM 09062X103 32,717 -5,239 -13.80 9,708 9.86 0.6360
2019-11-05 2019-09-30 13F Biogen IDEC COM 09062X103 37,956 36,196 2,056.59 8,837 2,044.90 0.6296
2019-07-30 2019-06-30 13F Biogen IDEC COM 09062X103 1,760 -1,000 -36.23 412 -36.91 0.0313
2019-05-02 2019-03-31 13F Biogen IDEC COM 09062X103 2,760 1,000 56.82 653 23.21 0.0512
2019-02-01 2018-12-31 13F Biogen IDEC COM 09062X103 1,760 -292 -14.23 530 -26.90 0.0517
2018-11-09 2018-09-30 13F Biogen IDEC COM 09062X103 2,052 92 4.69 725 27.42 0.0580
2018-08-10 2018-06-30 13F Biogen IDEC COM 09062X103 1,960 630 47.37 569 56.32 0.0503
2018-05-07 2018-03-31 13F Biogen IDEC COM 09062X103 1,330 -35 -2.56 364 -16.32 0.0353
2018-02-05 2017-12-31 13F Biogen IDEC COM 09062X103 1,365 0 0.00 435 1.87 0.0420
2017-11-03 2017-09-30 13F Biogen IDEC COM 09062X103 1,365 0 0.00 427 15.41 0.0454
2017-07-18 2017-06-30 13F Biogen IDEC COM 09062X103 1,365 0 0.00 370 -0.80 0.0413
2017-05-01 2017-03-31 13F Biogen IDEC COM 09062X103 1,365 0 0.00 373 -3.62 0.0409
2017-01-24 2016-12-31 13F Biogen IDEC COM 09062X103 1,365 0 0.00 387 -9.37 0.0449
2016-10-24 2016-09-30 13F Biogen IDEC COM 09062X103 1,365 -220 -13.88 427 11.49 0.0571
2016-07-25 2016-06-30 13F Biogen IDEC COM 09062X103 1,585 0 0.00 383 -7.26 0.0512
2016-04-25 2016-03-31 13F Biogen IDEC COM 09062X103 1,585 140 9.69 413 -6.77 0.0531
2016-02-03 2015-12-31 13F Biogen IDEC COM 09062X103 1,445 -38 -2.56 443 2.31 0.0598
2015-10-08 2015-09-30 13F Biogen IDEC COM 09062X103 1,483 -200 -11.88 433 -36.32 0.0557
2015-08-11 2015-06-30 13F Biogen IDEC COM 09062X103 1,683 140 9.07 680 4.29 0.0958
2015-04-24 2015-03-31 13F Biogen IDEC COM 09062X103 1,543 4 0.26 652 24.90 0.1567
2015-02-12 2014-12-31 13F Biogen IDEC COM 09062X103 1,539 -38 -2.41 522 0.00 0.1349
2014-11-06 2014-09-30 13F Biogen IDEC COM 09062X103 1,577 50 3.27 522 8.52 0.1366
2014-07-28 2014-06-30 13F Biogen IDEC COM 09062X103 1,527 349 29.63 481 33.61 0.1260
2014-05-01 2014-03-31 13F Biogen IDEC COM 09062X103 1,178 215 22.33 360 33.83 0.1011
2014-02-03 2013-12-31 13F Biogen IDEC COM 09062X103 963 0 0.00 269 15.95 0.0804
2013-10-29 2013-09-30 13F Biogen IDEC COM 09062X103 963 963 232 0.0785
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.