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BIIB in the 13F filings

Biogen Inc · CUSIP 09062X103

Sector · Pharmaceuticals and biotechnologyTheme · Biological productsTheme · Healthcare: biopharma and medtech· L3VLUP-defined
Quarter
Q3 2026 · early filersQ2 2026Q1 2026Q4 2025Q3 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q1 2024Q4 2023
Quarter end
30 Sep 2025
the date the book describes
Filed
15 Dec 2025
latest of these filings; the earliest 29 Oct 2025
Managers listing it
21
at least, of 95 tracked, among listed positions
Comparable managers
95
filed both Q2 2025 and Q3 2025; 18 listed it in both
Shares listed
19,943,745
combined, among listed positions
Reported value
$2.8bn
combined, at the quarter end

Among the 95 comparable managers: 13 buyers (opened or added shares) and 8 sellers (trimmed or exited), at least, among listed positions. Their net change in shares is not known from listed positions, because at least one of them lists it in only one of the two quarters.

Managers listing BIIB in Q3 2025

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q2 2025, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

21 of 21 holders

ActionFiling
Wellington Management Group LLP4,246,504$595m0.10%Trimmed-551,91614 Nov 2025 (the filing on sec.gov)
Point72 Asset Management LP3,872,901$543m0.91%Added+41,17414 Nov 2025 (the filing on sec.gov)
Invesco Ltd2,418,127$339m0.05%Added+98,00113 Nov 2025 (the filing on sec.gov)
AQR Capital Management LLC1,783,581$249m0.16%Added+418,77614 Nov 2025 (the filing on sec.gov)
Balyasny Asset Management LLC1,234,149$173m0.22%Added+402,24414 Nov 2025 (the filing on sec.gov)
Millennium Management LLC1,111,190$156m0.07%Added+435,68814 Nov 2025 (the filing on sec.gov)
Renaissance Technologies LLC964,406$135m0.18%Trimmed-80,70013 Nov 2025 (the filing on sec.gov)
Man Group PLC918,025$129m0.22%Added+124,74314 Nov 2025 (the filing on sec.gov)
Marshall Wace LLP887,661$124m0.13%Addedn.a.13 Nov 2025 (the filing on sec.gov)
MFS Investment Management729,316$102munder 0.1%Added+11,68529 Oct 2025 (the filing on sec.gov)
Arrowstreet Capital LP380,791$53munder 0.1%Trimmed-243,58013 Nov 2025 (the filing on sec.gov)
Schonfeld Strategic Advisors LLC320,154$45m0.25%Added+256,16514 Nov 2025 (the filing on sec.gov)
Hudson Bay Capital Management LP253,151$35m0.12%Trimmed-14,58915 Dec 2025 (the filing on sec.gov)
Freestone Grove Partners LP218,866$31m0.23%Added+107,86214 Nov 2025 (the filing on sec.gov)
Two Sigma Investments LP205,233$29munder 0.1%Trimmed-302,30614 Nov 2025 (the filing on sec.gov)
Acadian Asset Management LLC195,251$27munder 0.1%Trimmed-4,21113 Nov 2025 (the filing on sec.gov)
Woodline Partners LP96,666$14m0.06%Added+1,10614 Nov 2025 (the filing on sec.gov)
Bridgewater Associates LP39,983$5.6munder 0.1%Newnew13 Nov 2025 (the filing on sec.gov)
Brevan Howard Capital Management LP33,511$4.7munder 0.1%Addedn.a.14 Nov 2025 (the filing on sec.gov)
ExodusPoint Capital Management LP31,931$4.5munder 0.1%Trimmed-97,56014 Nov 2025 (the filing on sec.gov)
PDT Partners LLC2,348$329kunder 0.1%Trimmed-29,31617 Nov 2025 (the filing on sec.gov)

Largest increases and reductions, by shares

Q2 2025 to Q3 2025, among managers that listed it in both quarters or opened it.

Increases

Reductions

New positions and exits

At least these many: a manager is shown exiting only where its own filing shows the position gone.

New (1)

Exited (0)

No exit shown by a manager’s own filing.

Ownership over time

Every quarter on file. A quarter-end value moves with the price as well as with the shares held; buyers and sellers count comparable managers, by shares.
17 in Q3 2024 to 12 in Q2 2026

Tracked managers listing it, at least.

0102030402014201620182020202220242026
the quarter shown share split complete books; unmarked quarters rest on listed positionsClick a quarter to open it.
BIIB by quarter
QuarterHoldersReported valueBuyersSellers
Q2 201323$12.7bnn.a.n.a.
Q3 201320$14.3bnn.a.n.a.
Q4 201320$16.1bnn.a.n.a.
Q1 201421$16.8bnn.a.n.a.
Q2 201418$16.8bnn.a.n.a.
Q3 201423$16.4bnn.a.n.a.
Q4 201422$15.7bnn.a.n.a.
Q1 201524$20.3bnn.a.n.a.
Q2 201524$20.5bnn.a.n.a.
Q3 201524$12.4bnn.a.n.a.
Q4 201527$11.9bnn.a.n.a.
Q1 201627$10.3bnn.a.n.a.
Q2 201624$9.5bnn.a.n.a.
Q3 201629$11.6bnn.a.n.a.
Q4 201631$10.9bnn.a.n.a.
Q1 201725$9.2bnn.a.n.a.
Q2 201728$9.8bnn.a.n.a.
Q3 201724$11.6bnn.a.n.a.
Q4 201722$11.8bnn.a.n.a.
Q1 201828$9.6bnn.a.n.a.
Q2 201825$8.9bnn.a.n.a.
Q3 201828$10.6bnn.a.n.a.
Q4 201828$9.0bnn.a.n.a.
Q1 201922$7.4bnn.a.n.a.
Q2 201928$7.2bnn.a.n.a.
Q3 201928$7.1bnn.a.n.a.
Q4 201927$7.7bnn.a.n.a.
Q1 202025$7.3bnn.a.n.a.
Q2 202029$5.1bnn.a.n.a.
Q3 202025$5.1bnn.a.n.a.
Q4 202022$4.6bnn.a.n.a.
Q1 202118$4.7bnn.a.n.a.
Q2 202125$5.4bnn.a.n.a.
Q3 202123$3.3bnn.a.n.a.
Q4 202125$3.7bnn.a.n.a.
Q1 202229$3.7bnn.a.n.a.
Q2 202225$3.4bnn.a.n.a.
Q3 202233$5.2bnn.a.n.a.
Q4 202228$5.0bnn.a.n.a.
Q1 202330$5.1bnn.a.n.a.
Q2 202323$4.4bnn.a.n.a.
Q3 202321$2.9bnn.a.n.a.
Q4 202317$2.8bn118
Q1 202416$2.5bn910
Q2 202414$2.5bn68
Q3 202417$2.6bn152
Q4 202420$2.6bn164
Q1 202522$2.4bn1510
Q2 202520$2.5bn155
Q3 202521$2.8bn138
Q4 202520$3.9bn1225
Q1 202616$3.9bn1322
Q2 202612$5.8bn1617

Compare with…

Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.

BIIB and GILD →BIIB and AMGN →BIIB and ARGX →Choose a stock to compare with BIIB →

How much of the picture this is

A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.

Which funds own BIIB, latest filings →Back to the 13F Explorer →