Company · Ownership research

Spero Therapeutics, Inc. SPRO

CIK 0001701108 · CUSIP 84833T103

Insider tradingInitial holdingsInstitutional holders

Quarter-end disclosures, not live holdings.

Several CUSIPs are reported for this company; this page shows CUSIP 84833T103 (SPRO), not CUSIP 84833T953 (SPRO), CUSIP 84833T903 (SPRO), and does not merge CUSIPs.

This page lists the top 20 of 60 rows by value; the complete set is available through the API.

Some filings reported values in thousands; those figures were scaled ×1,000 to dollars.

Top 20 institutions

Weight means this stock's share of the manager's own portfolio.

By reported value

#	Manager	Value	Manager weight	Change vs prior	Source
01	GSK plc CIK 1131399 · View history	$20.31M 9,190,606 shares	3.37%	0(0.00%)Unchanged	SEC filing ↗ Aug 13, 2026	▾
02	Pfizer Inc CIK 78003 · View history	$5.34M 2,362,348 shares	3.13%	0(0.00%)Unchanged	SEC filing ↗ Aug 13, 2026	▾
03	VANGUARD CAPITAL MANAGEMENT LLC CIK 2100119 · View history	$4.50M 2,036,226 shares	0.00%	+236.35K(+13.10%)Added	SEC filing ↗ Aug 13, 2026	▾
04	RENAISSANCE TECHNOLOGIES LLC CIK 1037389 · View history	$2.09M 947,904 shares	0.00%	-241.33K(-20.30%)Reduced	SEC filing ↗ Aug 13, 2026	▾
05	Alphabet Inc. CIK 1652044 · View history	$1.97M 889,979 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ Aug 7, 2026	▾
06	SUSQUEHANNA INTERNATIONAL GROUP, LLP CIK 1446194 · View history	$1.68M 759,290 shares	0.00%	+426.18K(+127.90%)Added	SEC filing ↗ Aug 14, 2026	▾
07	BlackRock, Inc. CIK 2012383 · View history	$1.31M 594,404 shares	0.00%	+161.20K(+37.20%)Added	SEC filing ↗ Aug 7, 2026	▾
08	GEODE CAPITAL MANAGEMENT, LLC CIK 1214717 · View history	$1.25M 566,329 shares	0.00%	+46.41K(+8.90%)Added	SEC filing ↗ Aug 12, 2026	▾
09	RAYMOND JAMES FINANCIAL INC CIK 720005 · View history	$1.15M 521,705 shares	0.00%	+521.71KNew	SEC filing ↗ Aug 14, 2026	▾
10	TWO SIGMA INVESTMENTS, LP CIK 1179392 · View history	$846.02K 382,814 shares	0.00%	-502.82K(-56.80%)Reduced	SEC filing ↗ Aug 14, 2026	▾
11	ARROWSTREET CAPITAL, LIMITED PARTNERSHIP CIK 1164508 · View history	$735.86K 332,970 shares	0.00%	+332.97KNew	SEC filing ↗ Aug 13, 2026	▾
12	VANGUARD FIDUCIARY TRUST CO CIK 933478 · View history	$635.70K 287,648 shares	0.00%	+23.53K(+8.90%)Added	SEC filing ↗ Aug 13, 2026	▾
13	GSA CAPITAL PARTNERS LLP CIK 1362033 · View history	$632.00K 285,906 shares	0.04%	+7.60K(+2.70%)Added	SEC filing ↗ Aug 6, 2026	▾
14	DIMENSIONAL FUND ADVISORS LP CIK 354204 · View history	$607.62K 274,820 shares	0.00%	+245.05K(+823.20%)Added	SEC filing ↗ Aug 11, 2026	▾
15	GOLDMAN SACHS GROUP INC CIK 886982 · View history	$567.94K 256,985 shares	0.00%	+256.99KNew	SEC filing ↗ Aug 14, 2026	▾
16	STATE STREET CORP CIK 93751 · Amended · View history	$474.60K 214,751 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ Sep 22, 2026	▾
17	JANE STREET GROUP, LLC CIK 1595888 · View history	$349.39K 158,097 shares	0.00%	+51.75K(+48.70%)Added	SEC filing ↗ Aug 14, 2026	▾
18	UBS Group AG CIK 1610520 · View history	$308.69K 139,680 shares	0.00%	+136.67K(+4,542.10%)Added	SEC filing ↗ Aug 13, 2026	▾
19	BRIDGEWAY CAPITAL MANAGEMENT, LLC CIK 1107261 · View history	$253.71K 114,800 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ Aug 14, 2026	▾
20	NORTHERN TRUST CORP CIK 73124 · View history	$239.29K 108,274 shares	0.00%	-12.71K(-10.50%)Reduced	SEC filing ↗ Aug 13, 2026	▾

Showing 20 / 60 institutions. The complete set is available through the API.

Coverage & totals by quarter

Reporting institutions

Cancelled or null records excluded

Disclosed shares

21,447,770

Not deduplicated across managers

Disclosed value

$47.49M

Not market cap or free float

Reporting institutions by quarter

Counts also change with data coverage and reporting entities; they do not measure net buying. Distinct managers with a live stock row in this CUSIP; totals may include overlapping filings and are not a share of the company.

Spero Therapeutics, Inc. · Q2 2026

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This page includes 20 of 60 reporting institutions. Log in to look up the full history beyond 3 years, use advanced screening & filtering, download CSV, and get the complete set through the Akkru API.

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Sources, coverage & how to read this data

Figures are as reported to the SEC and merged with later amendments where Akkru could match them. Preview limits apply to what is listed, not to the totals, which come from the complete reported data. Nothing is zero-filled: a missing quarter or month is shown as missing.