Biogen Inc.
MX ˙ BMV ˙ US09062X1037
SecurityMX:BIIB / Biogen Inc.
InstitutionProspera Financial Services Inc
Latest Disclosed Ownership1,610 shares
Latest Disclosed Value $ 295,143
Prospera Financial Services Inc reports 28.12% decrease in ownership of BIIB / Biogen Inc.

On April 14, 2026 - Prospera Financial Services Inc filed a 13F-HR form disclosing ownership of 1,610 shares of Biogen Inc. (MX:BIIB) valued at $295,143 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 9, 2026 disclosing 2,240 shares of Biogen Inc.. This represents a change in shares of -28.12% 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)
2026-04-14 2026-03-31 13F BIOGEN COM 09062X103 1,610 -630 -28.12 295 -25.13 0.0048
2026-02-09 2025-12-31 13F BIOGEN COM 09062X103 2,240 2,240 394 0.0065
2025-02-13 2024-12-31 13F BIOGEN COM 09062X103 0 -1,048 -100.00 0 -100.00
2024-11-07 2024-09-30 13F BIOGEN COM 09062X103 1,048 -424 -28.80 203 -40.47 0.0052
2024-08-13 2024-06-30 13F BIOGEN COM 09062X103 1,472 -312 -17.49 341 -11.20 0.0095
2024-08-13 2024-03-31 13F BIOGEN COM 09062X103 1,784 -607 -25.39 385 -37.86 0.0115
2024-02-14 2023-12-31 13F BIOGEN COM 09062X103 2,391 1,248 109.19 619 110.92 0.0205
2023-11-13 2023-09-30 13F BIOGEN COM 09062X103 1,143 -5,821 -83.59 294 -85.22 0.0114
2023-08-08 2023-06-30 13F BIOGEN COM 09062X103 6,964 678 10.79 1,984 13.51 0.0759
2023-05-12 2023-03-31 13F BIOGEN COM 09062X103 6,286 11 0.18 1,748 0.58 0.0718
2023-02-08 2022-12-31 13F BIOGEN COM 09062X103 6,275 6,275 1,738 0.0870
2022-10-27 2022-09-30 13F BIOGEN COM 09062X103 0 -463 -100.00 0 -100.00
2022-08-08 2022-06-30 13F BIOGEN COM 09062X103 463 -477 -50.74 94 -52.53 0.0048
2022-05-04 2022-03-31 13F BIOGEN COM 09062X103 940 20 2.17 198 -10.00 0.0083
2022-02-10 2021-12-31 13F BIOGEN COM 09062X103 920 -6,345 -87.34 220 -89.30 0.0095
2021-11-12 2021-09-30 13F BIOGEN COM 09062X103 7,265 6,404 743.79 2,056 589.93 0.1024
2021-08-16 2021-06-30 13F/A-1 BIOGEN COM 09062X103 861 -275 -24.21 298 -5.99 0.0149
2021-08-12 2021-06-30 13F BIOGEN COM 09062X103 861 -275 298 0.0153
2021-05-06 2021-03-31 13F BIOGEN COM 09062X103 1,136 1,136 317 0.0188
2021-02-12 2020-12-31 13F BIOGEN COM 09062X103 0 -26 -100.00 0 -100.00
2020-11-04 2020-09-30 13F BIOGEN COM 09062X103 26 -741 -96.61 7 -96.59 0.0027
2020-08-10 2020-06-30 13F BIOGEN COM 09062X103 767 767 205 0.0182
2020-02-12 2019-12-31 13F BIOGEN COM 09062X103 0 -2,651 -100.00 0 -100.00
2019-10-22 2019-09-30 13F BIOGEN COM 09062X103 2,651 2,651 617 0.0634
2019-02-13 2018-12-31 13F BIOGEN COM 09062X103 0 -1,397 -100.00 0 -100.00
2018-10-25 2018-09-30 13F BIOGEN COM 09062X103 1,397 -255 -15.44 411 -14.91 0.0766
2018-07-18 2018-06-30 13F BIOGEN COM 09062X103 1,652 535 47.90 483 58.36 0.0654
2018-04-12 2018-03-31 13F BIOGEN COM 09062X103 1,117 -602 -35.02 305 -45.83 0.0426
2018-01-23 2017-12-31 13F BIOGEN COM 09062X103 1,719 1,010 142.45 563 152.47 0.0860
2017-10-11 2017-09-30 13F BIOGEN COM 09062X103 709 709 223 0.0339
2017-07-19 2017-06-30 13F BIOGEN COM 09062X103 0 -964 -100.00 0 -100.00
2017-04-13 2017-03-31 13F BIOGEN COM 09062X103 964 -39 -3.89 262 -9.97 0.0472
2017-01-11 2016-12-31 13F BIOGEN COM 09062X103 1,003 105 11.69 291 3.56 0.0570
2016-10-12 2016-09-30 13F BIOGEN COM 09062X103 898 -449 -33.33 281 -13.80 0.0564
2016-07-26 2016-06-30 13F BIOGEN COM 09062X103 1,347 390 40.75 326 30.92 0.0674
2016-04-12 2016-03-31 13F BIOGEN COM 09062X103 957 -567 -37.20 249 -46.68 0.0554
2016-01-12 2015-12-31 13F BIOGEN COM 09062X103 1,524 -370 -19.54 467 -15.55 0.1024
2015-10-16 2015-09-30 13F BIOGEN COM 09062X103 1,894 -39 -2.02 553 -26.17 0.1399
2015-08-07 2015-06-30 13F BIOGEN COM 09062X103 1,933 599 44.90 749 41.32 0.1782
2015-04-22 2015-03-31 13F BIOGEN COM 09062X103 1,334 -18 -1.33 530 15.47 0.1180
2015-01-14 2014-12-31 13F BIOGEN IDEC COM 09062X103 1,352 1,352 459 0.1144
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.