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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
31 Dec 2023
the date the book describes
Filed
16 Feb 2024
latest of these filings; the earliest 8 Feb 2024
Managers listing it
17
at least, of 95 tracked, among listed positions
Comparable managers
93
filed both Q3 2023 and Q4 2023; 13 listed it in both
Shares listed
10,936,904
combined, among listed positions
Reported value
$2.8bn
combined, at the quarter end

Among the 93 comparable managers: 11 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 Q4 2023

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q3 2023, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

17 of 17 holders

ActionFiling
Wellington Management Group LLP5,324,396$1.4bn0.26%Trimmed-49,91412 Feb 2024 (the filing on sec.gov)
Invesco Ltd1,814,666$470m0.11%Added+633,29213 Feb 2024 (the filing on sec.gov)
T. Rowe Price Associates Inc1,508,346$390m0.05%Added+344,81616 Feb 2024 (the filing on sec.gov)
Renaissance Technologies LLC758,606$196m0.30%Trimmed-327,79113 Feb 2024 (the filing on sec.gov)
MFS Investment Management580,065$150munder 0.1%Added+133,4638 Feb 2024 (the filing on sec.gov)
Balyasny Asset Management LLC317,302$82m0.15%Added+86,89114 Feb 2024 (the filing on sec.gov)
Bridgewater Associates LP143,286$37m0.21%Trimmed-7,59114 Feb 2024 (the filing on sec.gov)
Hudson Bay Capital Management LP135,000$35m0.22%Added+52,50014 Feb 2024 (the filing on sec.gov)
Moore Capital Management LP90,000$23m0.40%Added+30,00014 Feb 2024 (the filing on sec.gov)
Woodline Partners LP80,600$21m0.23%Newnew14 Feb 2024 (the filing on sec.gov)
Man Group PLC70,008$18m0.05%Trimmed-38,16014 Feb 2024 (the filing on sec.gov)
Caxton Associates LLP45,000$12m0.60%Newnew14 Feb 2024 (the filing on sec.gov)
Capital World Investors34,200$8.8munder 0.1%Newnew13 Feb 2024 (the filing on sec.gov)
Verition Fund Management LLC17,065$4.4munder 0.1%Trimmed-194,97114 Feb 2024 (the filing on sec.gov)
Eisler Capital Management Ltd10,639$2.8munder 0.1%Trimmed-23,05213 Feb 2024 (the filing on sec.gov)
PDT Partners LLC6,125$1.6m0.18%Added+4,52514 Feb 2024 (the filing on sec.gov)
Maverick Capital Ltd1,600$414kunder 0.1%Newnew14 Feb 2024 (the filing on sec.gov)

Largest increases and reductions, by shares

Q3 2023 to Q4 2023, 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 (4)

Exited (2)

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 →