SPRO
Spero Therapeutics, Inc.
$2.20
-0.02 (-0.90%)
At close · Jul 2
Market Cap
$127.38M
Shares
57,901,493
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.
Holders: 50
Total Value: $48,712,323
Total Shares: 20,817,241
Institutional Ownership Trend
25 quarters
Holder Concentration
Across 50 13F filers · Δ vs Dec 31, 2025Top Holder
44.1%
+0.9 pts
Top 5
74.1%
−0.3 pts
Top 10
87.0%
+1.1 pts
HHI
2,253
Moderately concentrated+67
Quarterly Activity
vs Dec 31, 2025
New
8
Increased
12
Decreased
11
Sold Out
14
Unchanged
19
Holder count:
-6
Institutional value:
-1.5%
Shares held:
-1.9%
Top Buyers
vs Dec 31, 2025| Institution | Added | Now Holds | Open |
|---|---|---|---|
| Mega TWO SIGMA INVESTMENTS, LP | +513,061 | 885,631 | |
| Mid GSA CAPITAL PARTNERS LLP | +99,374 | 278,304 | |
| Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP | +87,915 | 381,615 | |
| Large Squarepoint Ops LLC | +74,867 | 194,301 | |
| Mega Invesco Ltd. | +20,669 | 45,374 |
Top Sellers
vs Dec 31, 2025| Institution | Sold | Now Holds | Open |
|---|---|---|---|
| Small Anson Funds Management LP | −203,106 | 421,956 | |
| Micro INTREPID FAMILY OFFICE LLC | −148,721 | 16,279 | |
| Mega UBS Group AG | −113,438 | 3,009 | |
| Large OMERS ADMINISTRATION Corp | −91,727 | 39,400 | |
| Large RENAISSANCE TECHNOLOGIES LLC | −90,287 | 1,189,235 |
Top New Positions
vs Dec 31, 2025| Institution | Acquired | Value (USD) | Open |
|---|---|---|---|
| Mega VANGUARD CAPITAL MANAGEMENT LLC | 1,799,880 | $4,211,719 | |
| Mega VANGUARD FIDUCIARY TRUST CO | 264,115 | $618,029 | |
| Large MARSHALL WACE, LLP | 157,072 | $367,548 | |
| Micro Verdad Advisers, LP | 33,455 | $78,284 | |
| Mega Vanguard Global Advisers, LLC | 25,446 | $59,543 |
Top Sold-Out Positions
vs Dec 31, 2025| Institution | Previously Held | Last Value (USD) | Open |
|---|---|---|---|
| Mega VANGUARD GROUP INC | 2,083,462 | $4,854,465 | |
| Small Informed Momentum Co LLC | 218,084 | $508,135 | |
| Large TWO SIGMA ADVISERS, LP | 216,600 | $504,678 | |
| Large SEI INVESTMENTS CO | 132,010 | $307,582 | |
| Mid ADAR1 Capital Management, LLC | 113,839 | $265,244 |
| Holder | Value (USD) | % of 13F | Shares | Type | Discretion | Filed | Open | |||
|---|---|---|---|---|---|---|---|---|---|---|
| Small GSK plc | $21,506,018 | 44.15% | 9,190,606 | Shares | Sole | 2026-05-14 | ||||
| Small Pfizer Inc | $5,527,894 | 11.35% | 2,362,348 | Shares | Sole | 2026-05-12 | ||||
| Mega VANGUARD CAPITAL MANAGEMENT LLC | $4,211,719 | 8.65% | 1,799,880 | Shares | Defined | 2026-05-15 | ||||
| Large RENAISSANCE TECHNOLOGIES LLC | $2,782,809 | 5.71% | 1,189,235 | Shares | Sole | 2026-05-14 | ||||
| Mid Alphabet Inc. | $2,082,550 | 4.28% | 889,979 | Shares | Defined | 2026-05-08 | ||||
| Mega TWO SIGMA INVESTMENTS, LP | $2,072,376 | 4.25% | 885,631 | Shares | Sole | 2026-05-15 | ||||
| Mega GEODE CAPITAL MANAGEMENT, LLC | $1,216,617 | 2.50% | 519,922 | Shares | Defined | 2026-05-15 | ||||
| Mega BlackRock, Inc. | $1,013,692 | 2.08% | 433,202 | Shares | Sole | 2026-05-13 | ||||
| Small Anson Funds Management LP | $987,377 | 2.03% | 421,956 | Shares | Defined | 2026-05-19 | ||||
| Mega CITADEL ADVISORS LLC | $880,911 | 1.81% | 376,458 | Shares | Defined | 2026-05-15 | ||||
| Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP | $779,488 | 1.60% | 333,115 | Shares | Other | 2026-05-15 | ||||
| Mid GSA CAPITAL PARTNERS LLP | $651,231 | 1.34% | 278,304 | Shares | Sole | 2026-05-08 | ||||
| Mega VANGUARD FIDUCIARY TRUST CO Bank | $618,029 | 1.27% | 264,115 | Shares | Defined | 2026-05-08 | ||||
| Mega STATE STREET CORP | $502,517 | 1.03% | 214,751 | Shares | Defined | 2026-05-15 | ||||
| Small Ionic Capital Management LLC | $458,497 | 0.94% | 195,939 | Shares | Defined | 2026-05-15 | ||||
| Large Squarepoint Ops LLC | $454,664 | 0.93% | 194,301 | Shares | Defined | 2026-05-15 | ||||
| Large MARSHALL WACE, LLP | $367,548 | 0.75% | 157,072 | Shares | Other | 2026-05-15 | ||||
| Mega NORTHERN TRUST CORP Bank | $283,102 | 0.58% | 120,984 | Shares | Defined | 2026-05-14 | ||||
| Mid BRIDGEWAY CAPITAL MANAGEMENT, LLC | $268,632 | 0.55% | 114,800 | Shares | Sole | 2026-05-15 | ||||
| Mega JANE STREET GROUP, LLC | $248,846 | 0.51% | 106,345 | Shares | Defined | 2026-05-12 | ||||
| Mid Shay Capital LLC | $164,628 | 0.34% | 70,354 | Shares | Sole | 2026-05-15 | ||||
| Large Point72 Asset Management, L.P. | $139,623 | 0.29% | 59,668 | Shares | Defined | 2026-05-15 | ||||
| Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP | $113,490 | 0.23% | 48,500 | Put | Other | 2026-05-15 | ||||
| Mega Invesco Ltd. | $106,175 | 0.22% | 45,374 | Shares | Defined | 2026-05-12 | ||||
| Mid Quadrature Capital Ltd | $93,899 | 0.19% | 40,128 | Shares | Other | 2026-05-15 | ||||
| Large OMERS ADMINISTRATION Corp | $92,196 | 0.19% | 39,400 | Shares | Sole | 2026-05-15 | ||||
| Mega JANE STREET GROUP, LLC | $90,090 | 0.18% | 38,500 | Put | Defined | 2026-05-12 | ||||
| Mega JANE STREET GROUP, LLC | $88,452 | 0.18% | 37,800 | Call | Defined | 2026-05-12 | ||||
| Micro Verdad Advisers, LP | $78,284 | 0.16% | 33,455 | Shares | Sole | 2026-05-15 | ||||
| Small Capital Asset Advisory Services LLC | $76,162 | 0.16% | 32,548 | Shares | Sole | 2026-04-24 | ||||
| Mid SIMPLEX TRADING, LLC | $70,911 | 0.15% | 30,304 | Shares | Sole | 2026-05-14 | ||||
| Small Three Seasons Wealth, LLC | $70,200 | 0.14% | 30,000 | Shares | Sole | 2026-05-05 | ||||
| Mega DIMENSIONAL FUND ADVISORS LP | $69,656 | 0.14% | 29,768 | Shares | Sole | 2026-05-07 | ||||
| Mega CHARLES SCHWAB INVESTMENT MANAGEMENT INC | $66,842 | 0.14% | 28,565 | Shares | Sole | 2026-05-15 | ||||
| Mega CITADEL ADVISORS LLC | $62,478 | 0.13% | 26,700 | Call | Defined | 2026-05-15 | ||||
| Mega Vanguard Global Advisers, LLC | $59,543 | 0.12% | 25,446 | Shares | Defined | 2026-05-08 | ||||
| Mega CITADEL ADVISORS LLC | $52,650 | 0.11% | 22,500 | Put | Defined | 2026-05-15 | ||||
| Large Schonfeld Strategic Advisors LLC | $47,534 | 0.10% | 20,314 | Shares | Sole | 2026-05-15 | ||||
| Mega CITIGROUP INC | $44,775 | 0.09% | 19,135 | Shares | Defined | 2026-05-11 | ||||
| Large Assenagon Asset Management S.A. | $43,608 | 0.09% | 18,636 | Shares | Sole | 2026-04-20 | ||||
| Small Torrey Growth & Income Advisors | $39,838 | 0.08% | 17,025 | Shares | Sole | 2026-04-21 | ||||
| Mid OCCUDO QUANTITATIVE STRATEGIES LP | $38,425 | 0.08% | 16,421 | Shares | Sole | 2026-05-15 | ||||
| Micro INTREPID FAMILY OFFICE LLC Family Office | $38,092 | 0.08% | 16,279 | Shares | Sole | 2026-05-15 | ||||
| Large JONES FINANCIAL COMPANIES LLLP | $17,966 | 0.04% | 7,678 | Shares | Sole | 2026-05-15 | ||||
| Small FNY Investment Advisers, LLC | $12,402 | 0.03% | 5,300 | Shares | Sole | 2026-04-15 | ||||
| Mega MORGAN STANLEY | $10,651 | 0.02% | 4,552 | Shares | Defined | 2026-05-15 | ||||
| Mega UBS Group AG | $7,041 | 0.01% | 3,009 | Shares | Defined | 2026-05-05 | ||||
| Large OSAIC HOLDINGS, INC. | $678 | 0.00% | 290 | Shares | Defined | 2026-05-15 | ||||
| Mega JPMORGAN CHASE & CO | $552 | 0.00% | 236 | Shares | Defined | 2026-05-13 | ||||
| Mega WELLS FARGO & COMPANY/MN | $468 | 0.00% | 200 | Shares | Defined | 2026-05-11 | ||||
| Large US BANCORP \DE\ Bank | $353 | 0.00% | 151 | Shares | Defined | 2026-05-15 | ||||
| Mega BNP PARIBAS ARBITRAGE, SA | $93 | 0.00% | 40 | Shares | Defined | 2026-05-12 | ||||
| Mid Farther Finance Advisors, LLC | $23 | 0.00% | 10 | Shares | Sole | 2026-04-07 | ||||
| Mid SBI Securities Co., Ltd. Broker-Dealer | $21 | 0.00% | 9 | Shares | Defined | 2026-04-28 | ||||
| Small Caitong International Asset Management Co., Ltd | $7 | 0.00% | 3 | Shares | Sole | 2026-05-11 | ||||
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