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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 Jun 2025
the date the book describes
Filed
18 Aug 2025
latest of these filings; the earliest 7 Aug 2025
Managers listing it
20
at least, of 95 tracked, among listed positions
Comparable managers
95
filed both Q1 2025 and Q2 2025; 14 listed it in both
Shares listed
20,231,031
combined, among listed positions
Reported value
$2.5bn
combined, at the quarter end

Among the 95 comparable managers: 15 buyers (opened or added shares) and 5 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 Q2 2025

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q1 2025, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

20 of 20 holders

ActionFiling
Wellington Management Group LLP4,798,420$603m0.11%Added+125,98314 Aug 2025 (the filing on sec.gov)
Point72 Asset Management LP3,831,727$481m0.94%Added+3,424,47014 Aug 2025 (the filing on sec.gov)
Invesco Ltd2,320,126$291munder 0.1%Added+55,11913 Aug 2025 (the filing on sec.gov)
D. E. Shaw & Co.1,366,207$172m0.12%Trimmed-219,36514 Aug 2025 (the filing on sec.gov)
AQR Capital Management LLC1,364,805$171m0.14%Trimmed-4,03714 Aug 2025 (the filing on sec.gov)
Renaissance Technologies LLC1,045,106$131m0.17%Added+240,60013 Aug 2025 (the filing on sec.gov)
Balyasny Asset Management LLC831,905$104m0.16%Added+45,68614 Aug 2025 (the filing on sec.gov)
Man Group PLC793,282$100m0.19%Added+27,96114 Aug 2025 (the filing on sec.gov)
MFS Investment Management717,631$90munder 0.1%Added+9,2168 Aug 2025 (the filing on sec.gov)
Millennium Management LLC675,502$85munder 0.1%Addedn.a.14 Aug 2025 (the filing on sec.gov)
Arrowstreet Capital LP624,371$78m0.06%Added+409,59113 Aug 2025 (the filing on sec.gov)
Two Sigma Investments LP507,539$64m0.11%Trimmed-371,79114 Aug 2025 (the filing on sec.gov)
Two Sigma Advisers LP455,500$57m0.12%Trimmed-221,90014 Aug 2025 (the filing on sec.gov)
Hudson Bay Capital Management LP267,740$34m0.11%Added+67,22018 Aug 2025 (the filing on sec.gov)
Acadian Asset Management LLC199,462$25m0.05%Addedn.a.7 Aug 2025 (the filing on sec.gov)
ExodusPoint Capital Management LP129,491$16m0.14%Addedn.a.13 Aug 2025 (the filing on sec.gov)
Freestone Grove Partners LP111,004$14m0.11%Newnew14 Aug 2025 (the filing on sec.gov)
Woodline Partners LP95,560$12m0.06%Trimmed-29,60214 Aug 2025 (the filing on sec.gov)
Schonfeld Strategic Advisors LLC63,989$8.0m0.05%Newnew14 Aug 2025 (the filing on sec.gov)
PDT Partners LLC31,664$4.0m0.22%Newnew14 Aug 2025 (the filing on sec.gov)

Largest increases and reductions, by shares

Q1 2025 to Q2 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 (3)

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 →