Company · Ownership research

Spero Therapeutics, Inc. SPRO

CIK 0001701108 · CUSIP 84833T103

Insider trading Initial holdings Institutional 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 39 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	Anson Funds Management LP CIK 1491072 · Amended · View history	$2.74M 3,798,932 shares	0.65%	-40.95K(-1.10%)Reduced	SEC filing ↗ May 28, 2025	▾
02	Pfizer Inc CIK 78003 · View history	$1.70M 2,362,348 shares	0.34%	0(0.00%)Unchanged	SEC filing ↗ May 13, 2025	▾
03	VANGUARD GROUP INC CIK 102909 · View history	$1.27M 1,763,620 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ May 9, 2025	▾
04	RENAISSANCE TECHNOLOGIES LLC CIK 1037389 · View history	$699.05K 970,907 shares	0.00%	-134.68K(-12.20%)Reduced	SEC filing ↗ May 14, 2025	▾
05	Alphabet Inc. CIK 1652044 · View history	$640.78K 889,979 shares	0.04%	0(0.00%)Unchanged	SEC filing ↗ May 2, 2025	▾
06	Murchinson Ltd. CIK 1838556 · View history	$629.22K 873,910 shares	0.09%	0(0.00%)Unchanged	SEC filing ↗ May 15, 2025	▾
07	ACADIAN ASSET MANAGEMENT LLC CIK 916542 · View history	$626.00K 871,212 shares	0.00%	-168.71K(-16.20%)Reduced	SEC filing ↗ May 21, 2025	▾
08	ADAR1 Capital Management, LLC CIK 1940272 · View history	$576.92K 801,277 shares	0.11%	0(0.00%)Unchanged	SEC filing ↗ May 15, 2025	▾
09	GEODE CAPITAL MANAGEMENT, LLC CIK 1214717 · View history	$378.00K 524,869 shares	0.00%	+43.74K(+9.10%)Added	SEC filing ↗ May 13, 2025	▾
10	BlackRock, Inc. CIK 2012383 · View history	$347.10K 482,082 shares	0.00%	-3.27K(-0.70%)Reduced	SEC filing ↗ May 2, 2025	▾
11	MONIMUS CAPITAL MANAGEMENT, LP CIK 1848831 · View history	$223.85K 310,908 shares	0.19%	0(0.00%)Unchanged	SEC filing ↗ May 15, 2025	▾
12	Atlas Venture Life Science Advisors, LLC CIK 1917529 · View history	$219.78K 305,255 shares	0.04%	0(0.00%)Unchanged	SEC filing ↗ May 14, 2025	▾
13	MACKENZIE FINANCIAL CORP CIK 919859 · View history	$150.50K 209,031 shares	0.00%	+21.47K(+11.40%)Added	SEC filing ↗ May 7, 2025	▾
14	BRIDGEWAY CAPITAL MANAGEMENT, LLC CIK 1107261 · View history	$111.46K 154,800 shares	0.00%	-30.00K(-16.20%)Reduced	SEC filing ↗ May 15, 2025	▾
15	STATE STREET CORP CIK 93751 · View history	$107.22K 148,911 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ May 15, 2025	▾
16	DAFNA Capital Management LLC CIK 1389933 · View history	$90.00K 125,000 shares	0.03%	0(0.00%)Unchanged	SEC filing ↗ May 15, 2025	▾
17	NORTHERN TRUST CORP CIK 73124 · View history	$72.67K 100,924 shares	0.00%	+14.48K(+16.70%)Added	SEC filing ↗ May 13, 2025	▾
18	Squarepoint Ops LLC CIK 1642575 · Amended · View history	$66.92K 92,939 shares	0.00%	+37.89K(+68.80%)Added	SEC filing ↗ May 15, 2025	▾
19	CITADEL ADVISORS LLC CIK 1423053 · View history	$44.15K 61,316 shares	0.00%	-111.56K(-64.50%)Reduced	SEC filing ↗ May 15, 2025	▾
20	JPMORGAN CHASE & CO CIK 19617 · View history	$43.79K 60,817 shares	0.00%	-807(-1.30%)Reduced	SEC filing ↗ May 12, 2025	▾

Showing 20 / 39 institutions. The complete set is available through the API.

Coverage & totals by quarter

Reporting institutions

Cancelled or null records excluded

Disclosed shares

15,108,016

Not deduplicated across managers

Disclosed value

$10.88M

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. · Q1 2025

Explore all 39 reporting institutions.

This page includes 20 of 39 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.