SPRO · Spero Therapeutics, Inc. · Holdings

$1.17 -0.02 (-1.68%) At close · Sep 9

Market Cap

$70.46M

58.23M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Use institutional holdings through the 13F API or MCP →

Quarter:

Holders: 62

Total Value: $47,827,839

Total Shares: 21,641,570

Institutional Ownership Trend

26 quarters

Holder Concentration

Across 62 13F filers · Δ vs Mar 31, 2026

Top Holder

42.5%

−1.7 pts

Top 5

71.3%

−2.8 pts

Top 10

84.6%

−2.5 pts

HHI

2,098

Moderately concentrated−155

Quarterly Activity

vs Mar 31, 2026

New

Increased

Decreased

Sold Out

Unchanged

Holder count: +12

Institutional value: -1.8%

Shares held: +4.0%

Top Buyers

vs Mar 31, 2026

Institution	Added	Now Holds
Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP	+425,975	807,590
Mega DIMENSIONAL FUND ADVISORS LP	+245,052	274,820
Mega VANGUARD CAPITAL MANAGEMENT LLC	+236,346	2,036,226
Mega BlackRock, Inc.	+161,202	594,404
Mega UBS Group AG	+136,671	139,680

Top Sellers

vs Mar 31, 2026

Institution	Sold	Now Holds
Mega TWO SIGMA INVESTMENTS, LP	−502,817	382,814
Mega CITADEL ADVISORS LLC	−360,058	65,600
Large RENAISSANCE TECHNOLOGIES LLC	−241,331	947,904
Small Ionic Capital Management LLC	−93,241	102,698
Mega NORTHERN TRUST CORP	−12,710	108,274

Top New Positions

vs Mar 31, 2026

Institution	Acquired	Value (USD)
Mega RAYMOND JAMES FINANCIAL INC	521,705	$1,152,968
Mega ARROWSTREET CAPITAL, LIMITED PARTNERSHIP	332,970	$735,863
Mega GOLDMAN SACHS GROUP INC	256,985	$567,936
Large Federation des caisses Desjardins du Quebec	91,900	$203,099
Mid XTX Topco Ltd	50,536	$111,684

Top Sold-Out Positions

vs Mar 31, 2026

Institution	Previously Held	Last Value (USD)
Mid Anson Funds Management LP	421,956	$987,377
Large Squarepoint Ops LLC	194,301	$454,664
Large MARSHALL WACE, LLP	157,072	$367,548
Large Quadrature Capital Ltd	40,128	$93,899
Large OMERS ADMINISTRATION Corp	39,400	$92,196

Filter: New 23 Increased 16 Reduced 7 Sold out 11 Unchanged 16

Showing 66 of 66

All Common Calls Puts

Compact Export CSV

Holder

Value (USD)

% of 13F

GSK plc

$20,311,239

42.47%

9,190,606

Pfizer Inc

$5,220,789

10.92%

2,362,348

VANGUARD CAPITAL MANAGEMENT LLC

$4,500,059

9.41%

2,036,226

RENAISSANCE TECHNOLOGIES LLC

$2,094,867

4.38%

947,904

Alphabet Inc.

$1,966,853

4.11%

889,979

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
GV Management Company, L.L.C.	889,979	$1,966,853	100.0%	Defined

SUSQUEHANNA INTERNATIONAL GROUP, LLP

$1,678,030

3.51%

759,290

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SUSQUEHANNA SECURITIES, LLC	759,290	$1,678,030	100.0%	Other

BlackRock, Inc.

$1,313,630

2.75%

594,404

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
BlackRock Investment Management, LLC	10,170	$22,475	1.7%	Sole
BlackRock Fund Advisors	151,203	$334,158	25.4%	Sole
BlackRock Institutional Trust Company, N.A.	432,009	$954,739	72.7%	Sole
Aperio Group, LLC	1,022	$2,258	0.2%	Sole

GEODE CAPITAL MANAGEMENT, LLC

$1,251,586

2.62%

566,329

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
GEODE CAPITAL MANAGEMENT TRUST COMPANY, LLC	101,959	$225,329	18.0%	Defined
Held directly	464,370	$1,026,257	82.0%	Defined

RAYMOND JAMES FINANCIAL INC

$1,152,968

2.41%

521,705

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
RAYMOND JAMES & ASSOCIATES	1,000	$2,210	0.2%	Defined
Raymond James Financial Services Advisors, Inc.	2,062	$4,557	0.4%	Defined
ClariVest Asset Management LLC joint	518,643	$1,146,201	99.4%	Defined

TWO SIGMA INVESTMENTS, LP

$846,018

1.77%

382,814

ARROWSTREET CAPITAL, LIMITED PARTNERSHIP

$735,863

1.54%

332,970

VANGUARD FIDUCIARY TRUST CO

$635,702

1.33%

287,648

GSA CAPITAL PARTNERS LLP

$631,852

1.32%

285,906

DIMENSIONAL FUND ADVISORS LP

$607,350

1.27%

274,820

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Dimensional Fund Advisors Ltd.	4,957	$10,954	1.8%	Defined
Dimensional Ireland Ltd	50,499	$111,602	18.4%	Defined
Held directly	219,364	$484,794	79.8%	Sole

GOLDMAN SACHS GROUP INC

$567,936

1.19%

256,985

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
GOLDMAN SACHS & CO. LLC	256,985	$567,936	100.0%	Defined

STATE STREET CORP

$474,599

0.99%

214,751

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
STATE STREET GLOBAL ADVISORS TRUST COMPANY	214,751	$474,599	100.0%	Defined

JANE STREET GROUP, LLC

$349,394

0.73%

158,097

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	158,097	$349,394	100.0%	Defined

UBS Group AG

$308,692

0.65%

139,680

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
UBS AG	139,680	$308,692	100.0%	Defined

BRIDGEWAY CAPITAL MANAGEMENT, LLC

$253,708

0.53%

114,800

NORTHERN TRUST CORP

$239,285

0.50%

108,274

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
NORTHERN TRUST CO joint	108,274	$239,285	100.0%	Defined

Point72 Asset Management, L.P.

$230,673

0.48%

104,377

Ionic Capital Management LLC

$226,962

0.47%

102,698

Federation des caisses Desjardins du Quebec

$203,099

0.42%

91,900

Shay Capital LLC

$159,984

0.33%

72,391

CITADEL ADVISORS LLC

$144,976

0.30%

65,600

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	65,600	$144,976	100.0%	Defined

Invesco Ltd.

$141,981

0.30%

64,245

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Invesco Capital Management LLC	64,245	$141,981	100.0%	Defined

SIMPLEX TRADING, LLC

$135,499

0.28%

61,312

Verdad Advisers, LP

$113,450

0.24%

51,335

XTX Topco Ltd

$111,684

0.23%

50,536

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
XTX EXECUTION SERVICES LLC joint	50,536	$111,684	100.0%	Defined

JANE STREET GROUP, LLC

$104,091

0.22%

47,100

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	47,100	$104,091	100.0%	Defined

AMERICAN CENTURY COMPANIES INC

$81,352

0.17%

36,811

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
AMERICAN CENTURY INVESTMENT MANAGEMENT INC	36,811	$81,352	100.0%	Defined

SUSQUEHANNA INTERNATIONAL GROUP, LLP

$76,466

0.16%

34,600

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SUSQUEHANNA SECURITIES, LLC	34,600	$76,466	100.0%	Other

Capital Asset Advisory Services LLC

$71,931

0.15%

32,548

AXXCESS WEALTH MANAGEMENT, LLC

$71,931

0.15%

32,548

DLK Investment Management, LLC

$69,294

0.14%

31,355

Three Seasons Wealth, LLC

$66,300

0.14%

30,000

CHARLES SCHWAB INVESTMENT MANAGEMENT INC

$63,128

0.13%

28,565

JANE STREET GROUP, LLC

$59,228

0.12%

26,800

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	26,800	$59,228	100.0%	Defined

Vanguard Global Advisers, LLC

$56,235

0.12%

25,446

Global Retirement Partners, LLC

$55,250

0.12%

25,000

OPPENHEIMER & CO INC

$50,498

0.11%

22,850

MILLENNIUM MANAGEMENT LLC

$42,648

0.09%

19,298

Assenagon Asset Management S.A.

$41,185

0.09%

18,636

Susquehanna Portfolio Strategies, LLC

$38,957

0.08%

17,628

SUSQUEHANNA FUNDAMENTAL INVESTMENTS, LLC

$35,569

0.07%

16,095

SUSQUEHANNA INTERNATIONAL GROUP, LLP

$30,277

0.06%

13,700

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SUSQUEHANNA SECURITIES, LLC	13,700	$30,277	100.0%	Other

Qube Research & Technologies Ltd

$30,153

0.06%

13,644

SG Americas Securities, LLC

$24,902

0.05%

11,268

GROUP ONE TRADING LLC

$24,020

0.05%

10,869

TWO SIGMA SECURITIES, LLC

$23,372

0.05%

10,576

PRUDENTIAL FINANCIAL INC

$22,984

0.05%

10,400

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
PGIM Quantitative Solutions LLC	10,400	$22,984	100.0%	Defined

CITIGROUP INC

$21,271

0.04%

9,625

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citigroup Financial Products Inc. joint	9,625	$21,271	100.0%	Defined

FNY Investment Advisers, LLC

$18,343

0.04%

8,300

JONES FINANCIAL COMPANIES LLLP

$16,968

0.04%

7,678

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Edward D. Jones & Co., L.P.	7,678	$16,968	100.0%	Sole

Integrated Wealth Concepts LLC

$13,260

0.03%

6,000

ROYAL BANK OF CANADA

$4,450

0.01%

2,014

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
RBC Capital Markets, LLC	2,014	$4,450	100.0%	Defined

MORGAN STANLEY

$2,019

0.00%

914

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
MORGAN STANLEY & CO. LLC	1	$2	0.1%	Defined
MORGAN STANLEY SMITH BARNEY LLC	900	$1,989	98.5%	Defined
PARAMETRIC PORTFOLIO ASSOCIATES LLC	13	$28	1.4%	Defined

FMR LLC

$663

0.00%

300

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Fidelity Management & Research Co LLC	300	$663	100.0%	Defined

OSAIC HOLDINGS, INC.

$640

0.00%

290

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
OSAIC WEALTH, INC.	290	$640	100.0%	Defined

JPMORGAN CHASE & CO

$521

0.00%

236

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
J.P. Morgan Securities plc	236	$521	100.0%	Defined

WELLS FARGO & COMPANY/MN

$442

0.00%

200

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
WELLS FARGO CLEARING SERVICES, LLC	200	$442	100.0%	Defined

Rialto Wealth Management, LLC

$380

0.00%

172

US BANCORP \DE\

$333

0.00%

151

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
US BANK NATIONAL ASSOCIATION	151	$333	100.0%	Defined

SBI Securities Co., Ltd.

$28

0.00%

Farther Finance Advisors, LLC

$22

0.00%

INTERNATIONAL ASSETS INVESTMENT MANAGEMENT, LLC

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Squarepoint Capital LLP	194,301	$454,664	100.0%	Defined

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Marshall Wace North America L.P. joint	157,072	$367,548	100.0%	Other

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Quadrature US Inc.	40,128	$93,899	100.0%	Other

Key facts CIK 1701108 CUSIP 84833T103 13F (30d) 48 filings 48 filers Visit website