SPRO Spero Therapeutics, Inc.

NASDAQ
$1.03

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 September 30, 2026.

Managers compared
21
filed both this quarter and last
Managers holding
17
+1 on the quarter
Buyers
8
5 opened new
Sellers
8
4 sold out entirely
Buyer share
50.0%
of managers who traded it
Breadth
+0.0
net buyers, as a share of those trading

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Ownership map

Each block is one manager, sized by shares held and colored by how much they moved the position last quarter. Green added, red cut, grey stood pat.

Cut Unchanged Added Color saturates at ±50%.

Largest holders

Manager Shares % of reported
GSK plc 9.2M 77.6%
MACKENZIE FINANCIAL CORP 1.8M 15.5%
GEODE CAPITAL MANAGEMENT, LLC 499.3K 4.2%
DIMENSIONAL FUND ADVISORS LP 91.3K 0.8%
StoneX Group Inc. 38.2K 0.3%
SIMPLEX TRADING, LLC 36.8K 0.3%
Capital Asset Advisory Services LLC 32.5K 0.3%
Three Seasons Wealth, LLC 30.0K 0.3%
OPPENHEIMER & CO INC 26.8K 0.2%
FNY Investment Advisers, LLC 21.3K 0.2%
RITHOLTZ WEALTH MANAGEMENT 20.7K 0.2%
Assenagon Asset Management S.A. 17.8K 0.1%
Torrey Growth & Income Advisors 11.0K 0.1%
US BANCORP \DE\ 151 0.0%
SBI Securities Co., Ltd. 61 0.0%
Farther Finance Advisors, LLC 10 0.0%
BARCLAYS PLC 6 0.0%

Largest changes

Manager Action Previous Current Change
MACKENZIE FINANCIAL CORP New 0 1.8M +1.8M
Alphabet Inc. Sold Out 890.0K 0 -890.0K
DIMENSIONAL FUND ADVISORS LP Reduced 274.8K 91.3K -183.5K
GEODE CAPITAL MANAGEMENT, LLC Reduced 566.3K 499.3K -67.1K
StoneX Group Inc. New 0 38.2K +38.2K
AXXCESS WEALTH MANAGEMENT, LLC Sold Out 32.5K 0 -32.5K
DLK Investment Management, LLC Sold Out 31.4K 0 -31.4K
SIMPLEX TRADING, LLC Reduced 61.3K 36.8K -24.5K
RITHOLTZ WEALTH MANAGEMENT New 0 20.7K +20.7K
Assenagon Asset Management S.A. Reduced 37.3K 17.8K -19.5K
FNY Investment Advisers, LLC Increased 8.3K 21.3K +13.0K
Torrey Growth & Income Advisors New 0 11.0K +11.0K
CITIGROUP INC Sold Out 9.6K 0 -9.6K
OPPENHEIMER & CO INC Increased 22.9K 26.8K +3.9K
SBI Securities Co., Ltd. Increased 13 61 +48
BARCLAYS PLC New 0 6 +6

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.