Biogen Inc.
MX ˙ BMV ˙ US09062X1037
SecurityMX:BIIB / Biogen Inc.
InstitutionTradewinds, LLC.
Latest Disclosed Ownership1,129 shares
Latest Disclosed Value $ 211,191
Tradewinds, LLC. ownership in BIIB / Biogen Inc.

On May 4, 2026 - Tradewinds, LLC. filed a 13F-HR form disclosing ownership of 1,129 shares of Biogen Inc. (MX:BIIB) valued at $211,191 USD as of March 31, 2026. The entity filed a previous 13F-HR on November 8, 2024 disclosing 0 shares of Biogen Inc..

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)
2026-05-04 2026-03-31 13F BIOGEN COM 09062X103 1,129 1,129 211 0.0681
2024-11-08 2024-09-30 13F BIOGEN COM 09062X103 0 -1,128 -100.00 0 -100.00
2024-08-14 2024-06-30 13F BIOGEN COM 09062X103 1,128 0 0.00 261 7.41 0.0804
2024-05-08 2024-03-31 13F BIOGEN COM 09062X103 1,128 -16 -1.40 243 -17.35 0.1027
2023-11-06 2023-09-30 13F BIOGEN COM 09062X103 1,144 1,144 294 0.1726
2023-08-15 2023-06-30 13F BIOGEN Stock 09062X103 0 -1,146 -100.00 0 -100.00
2023-04-06 2023-03-31 13F BIOGEN Stock 09062X103 1,146 -12,612 -91.67 319 -92.52 0.1931
2023-02-08 2022-12-31 13F BERKSHIRE HATHAWAY INC SERIES B Stock 09062X103 13,758 12,572 1,060.03 4,250 1,240.38 2.7390
2022-10-17 2022-09-30 13F BIOGEN Stock 09062X103 1,186 -13 -1.08 317 29.39 0.2303
2022-08-15 2022-06-30 13F BIOGEN Stock 09062X103 1,199 55 4.81 245 -17.23 0.1666
2024-02-05 2021-12-31 13F BIOGEN Stock 09062X103 1,144 1,144 296 0.3494
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.