Biogen Inc.
MX ˙ BMV ˙ US09062X1037
SecurityMX:BIIB / Biogen Inc.
InstitutionLeuthold Group, Llc
Latest Disclosed Ownership33,143 shares
Latest Disclosed Value $ 6,076,106
Leuthold Group, Llc reports 1.70% increase in ownership of BIIB / Biogen Inc.

On May 6, 2026 - Leuthold Group, Llc filed a 13F-HR form disclosing ownership of 33,143 shares of Biogen Inc. (MX:BIIB) valued at $6,076,106 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 5, 2026 disclosing 32,589 shares of Biogen Inc.. This represents a change in shares of 1.70% 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.

Upgrade to unlock premium data and export to Excel .

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)
2026-05-06 2026-03-31 13F Biogen COM 09062X103 33,143 554 1.70 6,076 5.95 0.6473
2026-02-05 2025-12-31 13F Biogen COM 09062X103 32,589 9,072 38.58 5,735 74.10 0.6193
2025-11-06 2025-09-30 13F Biogen COM 09062X103 23,517 23,517 3,294 0.3604
2021-05-17 2021-03-31 13F Biogen COM 09062X103 0 -10,358 -100.00 0 -100.00
2021-02-16 2020-12-31 13F Biogen COM 09062X103 10,358 -5,280 -33.76 2,536 -42.83 0.3343
2020-11-16 2020-09-30 13F Biogen COM 09062X103 15,638 -811 -4.93 4,436 0.80 0.6081
2020-08-14 2020-06-30 13F Biogen COM 09062X103 16,449 99 0.61 4,401 -14.92 0.6553
2020-05-15 2020-03-31 13F Biogen COM 09062X103 16,350 -1,513 -8.47 5,173 -2.40 0.9321
2020-02-14 2019-12-31 13F Biogen COM 09062X103 17,863 17,863 5,300 0.6901
2019-11-14 2019-09-30 13F Biogen COM 09062X103 0 -14,291 -100.00 0 -100.00
2019-08-14 2019-06-30 13F Biogen COM 09062X103 14,291 -772 -5.13 3,342 -6.15 0.4310
2019-05-15 2019-03-31 13F Biogen COM 09062X103 15,063 5,566 58.61 3,561 24.60 0.4790
2019-02-14 2018-12-31 13F Biogen COM 09062X103 9,497 -603 -5.97 2,858 -19.90 0.4096
2018-11-14 2018-09-30 13F Biogen COM 09062X103 10,100 10,100 3,568 0.3887
2018-05-15 2018-03-31 13F Biogen COM 09062X103 0 -24,619 -100.00 0 -100.00
2018-02-14 2017-12-31 13F Biogen COM 09062X103 24,619 5,648 29.77 7,843 32.04 0.7833
2017-11-14 2017-09-30 13F Biogen COM 09062X103 18,971 -89 -0.47 5,940 14.85 0.5999
2017-08-14 2017-06-30 13F Biogen COM 09062X103 19,060 -1,028 -5.12 5,172 -5.83 0.5541
2017-05-15 2017-03-31 13F Biogen COM 09062X103 20,088 -53 -0.26 5,492 -3.85 0.5917
2017-02-14 2016-12-31 13F Biogen COM 09062X103 20,141 -1,581 -7.28 5,712 -16.00 0.6390
2016-11-14 2016-09-30 13F Biogen COM 09062X103 21,722 21,722 0.00 6,800 0.7146
2016-08-15 2016-06-30 13F Biogen COM 09062X103 0 -13,413 -100.00 0 -100.00
2016-05-16 2016-03-31 13F Biogen COM 09062X103 13,413 274 2.09 3,492 -13.24 0.3807
2016-02-12 2015-12-31 13F Biogen COM 09062X103 13,139 748 6.04 4,025 11.31 0.4224
2015-11-16 2015-09-30 13F Biogen COM 09062X103 12,391 -2,108 -14.54 3,616 -38.26 0.3820
2015-08-14 2015-06-30 13F Biogen COM 09062X103 14,499 553 3.97 5,857 -0.54 0.5478
2015-05-15 2015-03-31 13F Biogen COM 09062X103 13,946 66 0.48 5,889 24.98 0.5468
2015-02-17 2014-12-31 13F Biogen Idec COM 09062X103 13,880 13,880 39.09 4,712 119.47 0.4630
2013-11-14 2013-09-30 13F Biogen Idec COM 09062X103 0 -9,979 -100.00 0 -100.00
2013-08-14 2013-06-30 13F Biogen Idec COM 09062X103 9,979 9,979 2,147 0.1989
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.