SPRO Spero Therapeutics, Inc.

NASDAQ
$1.22

Spero Therapeutics, Inc. (SPRO) Institutional Ownership

What the institutions did with SPRO last quarter, from their 13F filings. Counting managers rather than shares is the point: a single index fund adding to a position tells you far less than four hundred separate managers all deciding to. Positions as reported for the quarter ended June 30, 2026.

Managers reporting
71
filed a 13F this quarter
Managers holding
59
+9 on the quarter
Buyers
38
21 opened new
Sellers
18
12 sold out entirely
Buyer share
67.9%
of managers who traded it
Breadth
+35.7
net buyers, as a share of those trading

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Largest holders

Manager Shares % of reported
GSK plc 9.2M 42.8%
Pfizer Inc 2.4M 11.0%
VANGUARD CAPITAL MANAGEMENT LLC 2.0M 9.5%
RENAISSANCE TECHNOLOGIES LLC 947.9K 4.4%
Alphabet Inc. 890.0K 4.1%
SUSQUEHANNA INTERNATIONAL GROUP, LLP 759.3K 3.5%
BlackRock, Inc. 594.4K 2.8%
GEODE CAPITAL MANAGEMENT, LLC 566.3K 2.6%
RAYMOND JAMES FINANCIAL INC 521.7K 2.4%
TWO SIGMA INVESTMENTS, LP 382.8K 1.8%
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 333.0K 1.6%
VANGUARD FIDUCIARY TRUST CO 287.6K 1.3%
GSA CAPITAL PARTNERS LLP 285.9K 1.3%
DIMENSIONAL FUND ADVISORS LP 274.8K 1.3%
GOLDMAN SACHS GROUP INC 257.0K 1.2%
STATE STREET CORP 214.8K 1.0%
JANE STREET GROUP, LLC 158.1K 0.7%
UBS Group AG 139.7K 0.7%
BRIDGEWAY CAPITAL MANAGEMENT, LLC 114.8K 0.5%
NORTHERN TRUST CORP 108.3K 0.5%
Point72 Asset Management, L.P. 104.4K 0.5%
Ionic Capital Management LLC 102.7K 0.5%
Federation des caisses Desjardins du Quebec 91.9K 0.4%
Shay Capital LLC 72.4K 0.3%
Invesco Ltd. 64.2K 0.3%

Largest changes

Manager Action Previous Current Change
Anson Funds Management LP Sold Out 843.9K 0 -843.9K
RAYMOND JAMES FINANCIAL INC New 0 521.7K +521.7K
TWO SIGMA INVESTMENTS, LP Reduced 885.6K 382.8K -502.8K
SUSQUEHANNA INTERNATIONAL GROUP, LLP Increased 333.1K 759.3K +426.2K
CITADEL ADVISORS LLC Sold Out 376.5K 0 -376.5K
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP New 0 333.0K +333.0K
GOLDMAN SACHS GROUP INC New 0 257.0K +257.0K
DIMENSIONAL FUND ADVISORS LP Increased 29.8K 274.8K +245.1K
RENAISSANCE TECHNOLOGIES LLC Reduced 1.2M 947.9K -241.3K
VANGUARD CAPITAL MANAGEMENT LLC Increased 1.8M 2.0M +236.3K
Squarepoint Ops LLC Sold Out 194.3K 0 -194.3K
BlackRock, Inc. Increased 433.2K 594.4K +161.2K
MARSHALL WACE, LLP Sold Out 157.1K 0 -157.1K
UBS Group AG Increased 3.0K 139.7K +136.7K
Ionic Capital Management LLC Reduced 195.9K 102.7K -93.2K
Federation des caisses Desjardins du Quebec New 0 91.9K +91.9K
JANE STREET GROUP, LLC Increased 106.3K 158.1K +51.8K
XTX Topco Ltd New 0 50.5K +50.5K
GEODE CAPITAL MANAGEMENT, LLC Increased 519.9K 566.3K +46.4K
Point72 Asset Management, L.P. Increased 59.7K 104.4K +44.7K
Quadrature Capital Ltd Sold Out 40.1K 0 -40.1K
OMERS ADMINISTRATION Corp Sold Out 39.4K 0 -39.4K
AMERICAN CENTURY COMPANIES INC New 0 36.8K +36.8K
AXXCESS WEALTH MANAGEMENT, LLC New 0 32.5K +32.5K
DLK Investment Management, LLC New 0 31.4K +31.4K

13F filings are due 45 days after quarter end and cover long positions in U.S.-listed equities only, so this is a lagged and partial picture: shorts, bonds and foreign listings never appear. Options positions are excluded here rather than folded into the share counts. Political ownership is coming.