Biogen Inc.
US ˙ NasdaqGS ˙ US09062X1037

SecurityBIIB / Biogen Inc.
InstitutionKBC Group NV
Latest Disclosed Ownership234,692 shares
Latest Disclosed Value $ 43,026
KBC Group NV reports 339.51% increase in ownership of BIIB / Biogen Inc.

On May 7, 2026 - KBC Group NV filed a 13F-HR form disclosing ownership of 234,692 shares of Biogen Inc. (US:BIIB) valued at $43,026,084 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 26, 2026 disclosing 53,398 shares of Biogen Inc.. This represents a change in shares of 339.51% during the quarter. The current value of the position is $45,990,244 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)
2026-05-07 2026-03-31 13F BIOGEN COM 09062X103 234,692 181,294 339.51 43 377.78 0.0555
2026-01-26 2025-12-31 13F BIOGEN COM 09062X103 53,398 17,939 50.59 9 125.00 0.0214
2026-01-20 2025-09-30 13F BIOGEN COM 09062X103 35,459 255 0.72 5 0.00 0.0119
2025-08-08 2025-06-30 13F BIOGEN COM 09062X103 35,204 864 2.52 4 0.00 0.0119
2025-04-25 2025-03-31 13F BIOGEN COM 09062X103 34,340 850 2.54 5 -20.00 0.0146
2025-01-22 2024-12-31 13F BIOGEN COM 09062X103 33,490 261 0.79 5 -16.67 0.0141
2024-11-06 2024-09-30 13F BIOGEN COM 09062X103 33,229 -8,752 -20.85 6 -33.33 0.0195
2024-07-17 2024-06-30 13F BIOGEN COM 09062X103 41,981 -3,526 -7.75 10 0.00 0.0294
2024-05-08 2024-03-31 13F BIOGEN COM 09062X103 45,507 -5,329 -10.48 10 -30.77 0.0312
2024-02-13 2023-12-31 13F BIOGEN COM 09062X103 50,836 2,358 4.86 13 8.33 0.0466
2024-02-15 2023-09-30 13F/A-1 BIOGEN COM 09062X103 48,478 -23,832 -32.96 12 -40.00 0.0509
2023-11-22 2023-09-30 13F BIOGEN COM 09062X103 71,344 0 20 0.0846
2024-02-15 2023-06-30 13F/A-1 BIOGEN COM 09062X103 72,310 4,891 7.25 21 11.11 0.0847
2023-07-28 2023-06-30 13F BIOGEN COM 09062X103 71,344 5,188 20 0.0846
2024-02-14 2023-03-31 13F/A-1 BIOGEN COM 09062X103 67,419 28,878 74.93 19 80.00 0.0796
2023-05-04 2023-03-31 13F BIOGEN COM 09062X103 66,156 37,427 18 0.0867
2024-02-14 2022-12-31 13F/A-1 BIOGEN COM 09062X103 38,541 8,739 29.32 11 42.86 0.0518
2023-02-13 2022-12-31 13F BIOGEN COM 09062X103 28,729 -1,073 8 0.0000
2024-02-15 2022-09-30 13F/A-1 BIOGEN COM 09062X103 29,802 -2,394 -7.44 8 16.67 0.0414
2022-11-08 2022-09-30 13F BIOGEN COM 09062X103 28,729 -3,467 7,671 0.0401
2024-02-14 2022-06-30 13F/A-1 BIOGEN COM 09062X103 32,196 -1,433 -4.26 7 -14.29 0.0328
2022-07-26 2022-06-30 13F BIOGEN COM 09062X103 31,145 -2,484 6,352 0.0320
2024-02-14 2022-03-31 13F/A-1 BIOGEN COM 09062X103 33,629 -7,067 -17.37 7 -22.22 0.0280
2022-05-06 2022-03-31 13F BIOGEN COM 09062X103 33,629 -7,067 7,082 0.0261
2024-02-14 2021-12-31 13F/A-1 BIOGEN COM 09062X103 40,696 -5,801 -12.48 10 -99.93 0.0322
2022-02-03 2021-12-31 13F BIOGEN COM 09062X103 40,696 -5,801 9,763 0.0306
2021-11-10 2021-09-30 13F BIOGEN COM 09062X103 46,497 -1,133 -2.38 13,158 -20.22 0.0482
2022-02-15 2021-06-30 13F/A-1 BIOGEN COM 09062X103 47,630 483 1.02 16,493 25.05 0.0595
2021-08-11 2021-06-30 13F BIOGEN COM 09062X103 47,630 483 16,493 0.0595
2022-02-14 2021-03-31 13F/A-1 BIOGEN COM 09062X103 47,147 -1,939 -3.95 13,189 -89.03 0.0534
2021-04-26 2021-03-31 13F BIOGEN COM 09062X103 47,147 -1,939 13,190 0.0534
2022-02-14 2020-12-31 13F/A-1 BIOGEN COM 09062X103 49,086 -42,433 -46.37 120,192 362.95 0.0565
2021-02-10 2020-12-31 13F BIOGEN COM 09062X103 49,086 -42,433 12,020 0.0553
2022-02-14 2020-09-30 13F/A-1 BIOGEN COM 09062X103 91,519 2,295 2.57 25,962 8.76 0.1529
2020-10-28 2020-09-30 13F BIOGEN COM 09062X103 91,519 2,295 25,962 0.1536
2022-02-14 2020-06-30 13F/A-1 BIOGEN COM 09062X103 89,224 -43,920 -32.99 23,872 -43.33 0.1578
2020-08-10 2020-06-30 13F BIOGEN COM 09062X103 89,224 -43,920 23,871 0.1597
2020-05-04 2020-03-31 13F BIOGEN COM 09062X103 133,144 -10,479 -7.30 42,124 -1.16 0.3525
2020-02-11 2019-12-31 13F BIOGEN COM 09062X103 143,623 -11,623 -7.49 42,617 17.91 0.2694
2019-11-07 2019-09-30 13F BIOGEN COM 09062X103 155,246 154,740 30,581.03 36,145 30,531.36 0.2651
2019-12-03 2019-06-30 13F/A-2 BIOGEN COM 09062X103 506 0 0.00 118 -1.67 1.0251
2019-08-08 2019-06-30 13F/A-1 BIOGEN COM 09062X103 83,347 82,841 19,493 0.1509
2019-07-30 2019-06-30 13F BIOGEN COM 09062X103 83,347 -54,923 19,493
2019-12-03 2019-03-31 13F/A-2 BIOGEN COM 09062X103 506 0 0.00 120 -21.05 1.0906
2019-08-07 2019-03-31 13F/A-1 BIOGEN COM 09062X103 80,953 80,447 19,136 0.1577
2019-05-10 2019-03-31 13F BIOGEN COM 09062X103 80,953 32,149 19,136
2019-12-03 2018-12-31 13F/A-1 BIOGEN COM 09062X103 506 -230 -31.25 152 -41.54 1.7755
2019-01-31 2018-12-31 13F BIOGEN COM 09062X103 48,804 -19,355 14,686 163,599.8472
2019-12-03 2018-09-30 13F/A-1 BIOGEN COM 09062X103 736 0 0.00 260 21.50 2.5651
2018-11-14 2018-09-30 13F BIOGEN COM 09062X103 68,159 67,423 24,081 182,159.6964
2019-12-03 2018-06-30 13F/A-1 BIOGEN COM 09062X103 736 0 0.00 214 5.94 2.3636
2018-08-03 2018-06-30 13F BIOGEN COM 09062X103 80,622 -37,900 23,400 203,725.4064
2019-12-03 2018-03-31 13F/A-2 BIOGEN COM 09062X103 736 0 0.00 202 -13.68 2.1531
2018-08-03 2018-03-31 13F/A-1 BIOGEN COM 09062X103 118,522 117,786 32,453 0.3002
2018-05-09 2018-03-31 13F BIOGEN COM 09062X103 118,522 -3,893 32,453
2019-12-03 2017-12-31 13F/A-2 BIOGEN COM 09062X103 736 0 0.00 234 1.74 2.4947
2018-08-03 2017-12-31 13F/A-1 BIOGEN COM 09062X103 122,415 121,679 38,998 0.3335
2018-02-07 2017-12-31 13F BIOGEN COM 09062X103 122,415 42,703 38,998
2019-12-03 2017-09-30 13F/A-1 BIOGEN COM 09062X103 736 0 0.00 230 15.00 2.9370
2017-11-13 2017-09-30 13F BIOGEN COM 09062X103 79,712 433 24,960 226,552.4356
2019-12-03 2017-06-30 13F/A-1 BIOGEN COM 09062X103 736 -95,261 -99.23 200 -99.24 2.8612
2017-08-04 2017-06-30 13F BIOGEN COM 09062X103 79,279 -16,718 21,513 207,910.0330
2017-05-10 2017-03-31 13F BIOGEN COM 09062X103 95,997 -79,620 -45.34 26,247 -47.30 0.2369
2017-02-16 2016-12-31 13F BIOGEN COM 09062X103 175,617 19,369 12.40 49,801 1.82 0.4936
2016-11-03 2016-09-30 13F BIOGEN COM 09062X103 156,248 65,472 72.12 48,911 122.82 0.5778
2016-08-03 2016-06-30 13F BIOGEN COM 09062X103 90,776 267 0.29 21,951 -6.83 0.3140
2016-05-11 2016-03-31 13F BIOGEN COM 09062X103 90,509 -1,088 -1.19 23,561 -16.04 0.3914
2016-02-11 2015-12-31 13F BIOGEN COM 09062X103 91,597 5,427 6.30 28,061 11.59 0.5169
2015-11-12 2015-09-30 13F BIOGEN COM 09062X103 86,170 -25,637 -22.93 25,146 -44.32 0.5058
2015-12-16 2015-06-30 13F/A-1 BIOGEN COM 09062X103 111,807 -11,276 -9.16 45,163 -13.10 0.5805
2015-07-31 2015-06-30 13F BIOGEN COM 09062X103 111,807 45,163
2015-12-16 2015-03-31 13F/A-1 BIOGEN COM 09062X103 123,083 -14,952 -10.83 51,970 10.91 0.6602
2015-04-30 2015-03-31 13F BIOGEN COM 09062X103 123,083 51,970
2015-12-15 2014-12-31 13F/A-1 BIOGEN IDEC COM 09062X103 138,035 134,623 3,945.57 46,856 4,053.90 0.5580
2015-02-12 2014-12-31 13F BIOGEN IDEC COM 09062X103 138,035 46,856
2014-10-16 2014-09-30 13F BIOGEN IDEC COM 09062X103 3,412 -161,008 -97.92 1,128 -97.82 0.0394
2014-08-01 2014-06-30 13F BIOGEN IDEC COM 09062X103 164,420 54,064 48.99 51,843 53.59 0.5923
2014-04-30 2014-03-31 13F BIOGEN IDEC COM 09062X103 110,356 -3,960 -3.46 33,755 5.62 0.5330
2014-01-21 2013-12-31 13F BIOGEN IDEC COM 09062X103 114,316 -4,095 -3.46 31,960 12.10 0.4835
2013-11-06 2013-09-30 13F BIOGEN IDEC COM 09062X103 118,411 34,180 40.58 28,509 57.27 0.4588
2013-07-29 2013-06-30 13F BIOGEN IDEC COM 09062X103 84,231 84,231 18,127 0.3363
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.