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BIIB · ARGX in the 13F filings

Two to four stocks side by side among the 95 tracked managers: who lists them, how that has moved, who bought and sold in a quarter, and which managers hold more than one.

BIIBARGX
Quarter
Q2 2026Q1 2026Q4 2025Q3 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q1 2024Q4 2023

Holders over time

Tracked managers listing each stock every quarter, at least, or their combined reported value. A gap is a quarter in which no tracked manager listed it. Click a quarter to compare there.
  • BIIB
  • ARGX
010203040202120222023202420252026
Holders and value by quarter
QuarterBIIBARGX
Q3 202025 holders, $5.1bn8 holders, $3.6bn
Q4 202022 holders, $4.6bn7 holders, $4.1bn
Q1 202118 holders, $4.7bn8 holders, $4.1bn
Q2 202125 holders, $5.4bn9 holders, $4.6bn
Q3 202123 holders, $3.3bn8 holders, $4.5bn
Q4 202125 holders, $3.7bn9 holders, $5.3bn
Q1 202229 holders, $3.7bn8 holders, $5.3bn
Q2 202225 holders, $3.4bn13 holders, $6.5bn
Q3 202233 holders, $5.2bn14 holders, $5.3bn
Q4 202228 holders, $5.0bn13 holders, $5.5bn
Q1 202330 holders, $5.1bn13 holders, $5.9bn
Q2 202323 holders, $4.4bn18 holders, $6.6bn
Q3 202321 holders, $2.9bn21 holders, $8.7bn
Q4 202317 holders, $2.8bn17 holders, $6.3bn
Q1 202416 holders, $2.5bn13 holders, $6.8bn
Q2 202414 holders, $2.5bn14 holders, $7.9bn
Q3 202417 holders, $2.6bn13 holders, $10.7bn
Q4 202420 holders, $2.6bn14 holders, $12.3bn
Q1 202522 holders, $2.4bn17 holders, $11.8bn
Q2 202520 holders, $2.5bn18 holders, $10.8bn
Q3 202521 holders, $2.8bn16 holders, $13.8bn
Q4 202520 holders, $3.9bn16 holders, $14.8bn
Q1 202616 holders, $3.9bn11 holders, $12.3bn
Q2 202612 holders, $5.8bn14 holders, $15.0bn
BIIB

Biogen Inc

Holders
12
Reported value
$5.8bn
Buyers
16
Sellers
17

Breadth -1 among 91 comparable managers.

Pharmaceuticals and biotechnologyBiological productsHealthcare: biopharma and medtech · L3VLUP
ARGX

Argenx Se

Holders
14
Reported value
$15.0bn
Buyers
16
Sellers
15

Breadth +1 among 91 comparable managers.

Pharmaceuticals and biotechnologyBiological productsHealthcare: biopharma and medtech · L3VLUP

Who holds both, Q2 2026

Among the 22 tracked managers listing any of them. "Only" is about listed positions: a manager may hold the other below its listed range.

Only BIIB (8)

Acadian Asset Management LLC, AQR Capital Management LLC, Balyasny Asset Management LLC, Farallon Capital Management LLC, Freestone Grove Partners LP, Hudson Bay Capital Management LP, Man Group PLC, MFS Investment Management

Only ARGX (10)

AllianceBernstein LP, Artisan Partners LP, Baillie Gifford & Co, Capital Research Global Investors, Capital World Investors, Janus Henderson Group Ltd, Squarepoint Ops LLC, T. Rowe Price Associates Inc, Two Sigma Investments LP, Voloridge Investment Management LLC

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. Buyers and sellers count comparable managers (those that filed both quarters) by shares, so a rise in value with no rise in shares is the price. Large books are listed to their largest positions. These are 95 tracked managers, not the institutional market.

Back to the 13F Explorer →