BIIB Biogen Inc.

NASDAQ
$217.15

Biogen Inc. (BIIB) Hedge Fund Activity

This view isolates hedge funds from the broader institutional ownership shown on the Institutional tab. A pension fund tracking an index may have no view on a stock; when a hedge fund builds or exits a position, that decision can carry information. This page measures those changes. Positions as of June 30, 2026.

Based on quarterly 13F long-equity filings. Changes compare reported quarter-end positions; filings can be reported up to 45 days later and do not represent a fund's complete exposure.

Hedge fund breadth
-26.83
15 buyers / 26 sellers
STRONG SELLING
Funds compared
43
funds with comparable BIIB positions
32 current holders · 37 prior-quarter holders
Net share change
-1.90M
+1.03M added, -2.94M cut
Position activity
6 new 9 increased 15 reduced 11 exited

Most significant moves

Ranked by conviction, not size — how much of the fund's own book the position represents, how far it moved, and what kind of fund made it.

Fund Action Shares changed Change Est. value Portfolio wt. Score
Perceptive Advisors Growth Healthcare New +276.2K — $59.7M 0.9% 71
Logos Global Management Growth Healthcare Sold Out -200.0K -100.0% $43.2M 0.0% 69
Farallon Capital Management Event Value New +71.0K — $15.3M 0.1% 64
Glenview Capital Management Long/Short Value Sold Out -57.0K -100.0% $12.3M 0.0% 63
D. E. Shaw & Co., Inc. Quant New +74.4K — $16.1M 0.0% 62
MILLENNIUM MANAGEMENT LLC Sold Out -94.0K -100.0% $20.3M 0.0% 61
Point72 Asset Management, L.P. Reduced -721.5K -89.1% $155.9M 0.0% 60
Qube Research & Technologies Ltd Quant Sold Out -212.9K -100.0% $46.0M 0.0% 59
Tang Capital Management Growth Healthcare Sold Out -35.0K -100.0% $7.6M 0.0% 59
CITADEL ADVISORS LLC Quant Increased +280.3K +203.0% $60.6M 0.1% 58

Most significant buyers

By move score, not size.

  • Perceptive Advisors New · +276.2K
  • Farallon Capital Management New · +71.0K
  • D. E. Shaw & Co., Inc. New · +74.4K
  • CITADEL ADVISORS LLC Increased · +280.3K
  • Verition Fund Management New · +30.9K

Most significant sellers

By move score, not size.

  • Logos Global Management Sold Out · -200.0K
  • Glenview Capital Management Sold Out · -57.0K
  • MILLENNIUM MANAGEMENT LLC Sold Out · -94.0K
  • Point72 Asset Management, L.P. Reduced · -721.5K
  • Qube Research & Technologies Ltd Sold Out · -212.9K

Hedge fund positions

Fund Tier Shares Previous Change Change % Portfolio wt. Action Score
Perceptive Advisors 1 276.2K 0 +276.2K — 0.9% New 71
Logos Global Management 2 0 200.0K -200.0K -100.0% 0.0% Sold Out 69
Farallon Capital Management 1 71.0K 0 +71.0K — 0.1% New 64
Glenview Capital Management 2 0 57.0K -57.0K -100.0% 0.0% Sold Out 63
D. E. Shaw & Co., Inc. 1 74.4K 0 +74.4K — 0.0% New 62
MILLENNIUM MANAGEMENT LLC 2 0 94.0K -94.0K -100.0% 0.0% Sold Out 61
Point72 Asset Management, L.P. 1 88.1K 809.6K -721.5K -89.1% 0.0% Reduced 60
Qube Research & Technologies Ltd 2 0 212.9K -212.9K -100.0% 0.0% Sold Out 59
Tang Capital Management 2 0 35.0K -35.0K -100.0% 0.0% Sold Out 59
CITADEL ADVISORS LLC 1 418.4K 138.1K +280.3K +203.0% 0.1% Increased 58
Verition Fund Management 2 30.9K 0 +30.9K — 0.1% New 56
Schonfeld Strategic Advisors 3 0 48.8K -48.8K -100.0% 0.0% Sold Out 55
MARSHALL WACE, LLP 2 12.6K 229.9K -217.3K -94.5% 0.0% Reduced 53
Caption Management 3 21.0K 0 +21.0K — 0.2% New 53
Graham Capital Management 3 0 10.3K -10.3K -100.0% 0.0% Sold Out 52
LMR Partners 3 4.9K 116.1K -111.3K -95.8% 0.0% Reduced 51
Alphadyne Asset Management 3 0 1.2K -1.2K -100.0% 0.0% Sold Out 51
ExodusPoint Capital Management 3 2.9K 152.0K -149.1K -98.1% 0.0% Reduced 51
CenterBook Partners 4 10.4K 0 +10.4K — 0.1% New 51
Boothbay Fund Management 4 0 14.3K -14.3K -100.0% 0.0% Sold Out 51
Cinctive Capital Management 3 72.8K 19.3K +53.4K +276.2% 0.7% Increased 51
Winton Group 4 0 3.3K -3.3K -100.0% 0.0% Sold Out 48
Balyasny Asset Management L.P. 2 265.1K 650.0K -385.0K -59.2% 0.1% Reduced 48
Integral Health Asset Management 2 100.0K 60.0K +40.0K +66.7% 0.9% Increased 48
Engineers Gate 4 0 1.6K -1.6K -100.0% 0.0% Sold Out 48
RENAISSANCE TECHNOLOGIES LLC 1 77.7K 203.4K -125.7K -61.8% 0.0% Reduced 47
Walleye Capital 3 569 35.3K -34.8K -98.4% 0.0% Reduced 47
Palo Alto Investors 2 140.3K 140.7K -440 -0.3% 4.4% Reduced 46
Squarepoint Ops LLC 2 7.0K 36.1K -29.0K -80.6% 0.0% Reduced 46
ADAGE CAPITAL PARTNERS GP, L.L.C. 2 129.6K 333.5K -203.9K -61.1% 0.0% Reduced 44
Lighthouse Investment Partners 3 7.5K 32.6K -25.1K -77.0% 0.1% Reduced 42
Hudson Bay Capital Management 3 90.0K 201.4K -111.4K -55.3% 0.1% Reduced 41
ADAR1 Capital Management 3 17.9K 11.0K +6.9K +62.7% 0.2% Increased 41
Alyeska Investment Group, L.P. 2 932.4K 805.1K +127.3K +15.8% 0.6% Increased 36
Man Group 3 196.2K 318.7K -122.5K -38.4% 0.1% Reduced 35
Portolan Capital Management 3 142.9K 118.5K +24.4K +20.6% 1.2% Increased 34
TWO SIGMA INVESTMENTS, LP 2 7.1K 9.4K -2.3K -24.8% 0.0% Reduced 32
Gotham Asset Management, LLC 2 279.9K 298.4K -18.5K -6.2% 0.2% Reduced 28
Parallax Volatility Advisers 3 2.3K 1.7K +602 +35.6% 0.0% Increased 28
Woodline Partners LP 2 112.5K 109.0K +3.4K +3.1% 0.1% Increased 24
AQR Capital Management 3 1.9M 1.9M +13.3K +0.7% 0.1% Increased 23
OrbiMed Advisors 2 61.6K 61.6K 0 +0.0% 0.3% Unchanged 22
Holocene Advisors, LP 2 4.8K 4.8K 0 +0.0% 0.0% Unchanged 20

Every fund above opens. Subscribers can see any manager's whole portfolio — every position, its weight, and what they bought, trimmed and exited last quarter.

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Hedge funds are identified from their 13F filings, which are due 45 days after quarter end and cover long U.S.-listed equity positions only. A fund's short book never appears, so a reduced position can mean a changed view or a changed hedge — the filing doesn't say which.