Biogen Inc.
US ˙ NasdaqGS ˙ US09062X1037

SecurityBIIB / Biogen Inc.
InstitutionGreenleaf Trust
Latest Disclosed Ownership6,371 shares
Latest Disclosed Value $ 1,167,996
Greenleaf Trust reports 0.98% increase in ownership of BIIB / Biogen Inc.

On April 27, 2026 - Greenleaf Trust filed a 13F-HR form disclosing ownership of 6,371 shares of Biogen Inc. (US:BIIB) valued at $1,167,995 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 21, 2026 disclosing 6,309 shares of Biogen Inc.. This represents a change in shares of 0.98% during the quarter. The current value of the position is $1,248,461 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)
2026-04-27 2026-03-31 13F Biogen Idec Com 09062X103 6,371 62 0.98 1,168 5.14 0.0064
2026-01-21 2025-12-31 13F Biogen Idec Com 09062X103 6,309 190 3.11 1,110 29.52 0.0102
2025-10-22 2025-09-30 13F Biogen Idec Com 09062X103 6,119 450 7.94 857 20.53 0.0078
2025-07-17 2025-06-30 13F Biogen Idec Com 09062X103 5,669 2,714 91.84 712 75.99 0.0063
2025-04-30 2025-03-31 13F Biogen Idec Com 09062X103 2,955 -2,110 -41.66 404 -47.80 0.0037
2025-01-24 2024-12-31 13F Biogen Idec COM 09062X103 5,065 2,459 94.36 775 53.27 0.0070
2024-10-22 2024-09-30 13F Biogen Idec COM 09062X103 2,606 -3,475 -57.15 505 -64.16 0.0045
2024-07-22 2024-06-30 13F Biogen Idec COM 09062X103 6,081 4,610 313.39 1,410 344.48 0.0134
2024-04-29 2024-03-31 13F Biogen Idec COM 09062X103 1,471 -684 -31.74 317 -43.09 0.0029
2024-01-31 2023-12-31 13F Biogen Idec COM 09062X103 2,155 365 20.39 558 21.09 0.0060
2023-11-09 2023-09-30 13F Biogen Idec COM 09062X103 1,790 171 10.56 460 -0.22 0.0053
2023-08-09 2023-06-30 13F Biogen Idec COM 09062X103 1,619 19 1.19 461 3.83 0.0049
2023-05-11 2023-03-31 13F Biogen Idec COM 09062X103 1,600 -244 -13.23 445 0.0050
2023-01-25 2022-12-31 13F Biogen Idec COM 09062X103 1,844 719 63.91 1 -100.00 0.0065
2022-11-10 2022-09-30 13F Biogen Idec COM 09062X103 1,125 -1 -0.09 300 30.43 0.0044
2022-08-12 2022-06-30 13F Biogen Idec COM 09062X103 1,126 -602 -34.84 230 -36.81 0.0035
2022-04-27 2022-03-31 13F Biogen Idec COM 09062X103 1,728 -159 -8.43 364 -19.65 0.0043
2022-02-11 2021-12-31 13F Biogen Idec COM 09062X103 1,887 -1,514 -44.52 453 -52.91 0.0053
2021-11-12 2021-09-30 13F Biogen Idec COM 09062X103 3,401 1,298 61.72 962 32.14 0.0117
2021-08-10 2021-06-30 13F Biogen Idec COM 09062X103 2,103 -182 -7.96 728 13.93 0.0090
2021-04-30 2021-03-31 13F Biogen Idec COM 09062X103 2,285 532 30.35 639 48.95 0.0084
2021-02-08 2020-12-31 13F Biogen Idec COM 09062X103 1,753 -522 -22.95 429 -33.49 0.0057
2020-10-30 2020-09-30 13F Biogen Idec COM 09062X103 2,275 364 19.05 645 26.22 0.0100
2020-08-12 2020-06-30 13F Biogen Idec COM 09062X103 1,911 -217 -10.20 511 -24.07 0.0090
2020-04-29 2020-03-31 13F Biogen Idec COM 09062X103 2,128 517 32.09 673 40.79 0.0134
2020-02-11 2019-12-31 13F Biogen Idec COM 09062X103 1,611 22 1.38 478 29.19 0.0075
2019-11-08 2019-09-30 13F Biogen Idec COM 09062X103 1,589 -721 -31.21 370 -31.48 0.0057
2019-07-24 2019-06-30 13F Biogen Idec COM 09062X103 2,310 406 21.32 540 20.00 0.0085
2019-05-08 2019-03-31 13F Biogen Idec COM 09062X103 1,904 -655 -25.60 450 -41.56 0.0074
2019-02-07 2018-12-31 13F Biogen Idec COM 09062X103 2,559 115 4.71 770 -10.78 0.0152
2018-10-29 2018-09-30 13F Biogen Idec COM 09062X103 2,444 980 66.94 863 103.06 0.0156
2018-08-07 2018-06-30 13F Biogen Idec COM 09062X103 1,464 637 77.03 425 88.05 0.0081
2018-04-30 2018-03-31 13F Biogen Idec COM 09062X103 827 -80 -8.82 226 -21.80 0.0045
2018-02-08 2017-12-31 13F Biogen Idec COM 09062X103 907 76 9.15 289 11.15 0.0059
2017-11-13 2017-09-30 13F Biogen Idec COM 09062X103 831 831 260 0.0057
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.