CAMBRIDGE, MA
SPERO THERAPEUTICS, INC.SPRO— Latest position per institution from SEC 13F filings
15
Institutional holders
25.37M
Total shares held
52.60M
Estimated value
1.27M
Avg. position size
GSK PLC
CIK 1131399
Shares
9.19M
Value
20.31M
Filed
Jun 30, 2026
PFIZER INC
CIK 78003
Shares
2.36M
Value
5.34M
Filed
Jun 30, 2026
VANGUARD GROUP INC
CIK 102909
Shares
2.08M
Value
4.85M
Filed
Dec 31, 2025
VANGUARD CAPITAL MANAGEMENT LLC
CIK 2100119
Shares
2.04M
Value
4.50M
Filed
Jun 30, 2026
ATLAS VENTURE ASSOCIATES IX, LLC
CIK 1671207
Shares
1.35M
Value
1.64M
Filed
Sep 30, 2023
RENAISSANCE TECHNOLOGIES LLC
CIK 1037389
Shares
947.90K
Value
2.09M
Filed
Jun 30, 2026
ALPHABET INC.
CIK 1652044
Shares
889.98K
Value
1.97M
Filed
Jun 30, 2026
MURCHINSON LTD.
CIK 1838556
Shares
873.91K
Value
629.22K
Filed
Mar 31, 2025
SUSQUEHANNA INTERNATIONAL GROUP, LLP
CIK 1446194
Shares
807.59K
Value
1.78M
Filed
Jun 30, 2026
BLACKROCK, INC.
CIK 2012383
Shares
594.40K
Value
1.31M
Filed
Jun 30, 2026
GEODE CAPITAL MANAGEMENT, LLC
CIK 1214717
Shares
566.33K
Value
1.25M
Filed
Jun 30, 2026
RAYMOND JAMES FINANCIAL INC
CIK 720005
Shares
521.71K
Value
1.15M
Filed
Jun 30, 2026
BLACKROCK FINANCE, INC.
CIK 1364742
Shares
483.40K
Value
628.42K
Filed
Jun 30, 2024
NOVO HOLDINGS A/S
CIK 1388325
Shares
468.90K
Value
628.33K
Filed
Sep 30, 2024
ANSON FUNDS MANAGEMENT LP
CIK 1491072
Shares
421.96K
Value
987.38K
Filed
Mar 31, 2026
AMERIPRISE FINANCIAL INC
CIK 820027
Shares
402.96K
Value
592.36K
Filed
Dec 31, 2023
TWO SIGMA INVESTMENTS, LP
CIK 1179392
Shares
382.81K
Value
846.02K
Filed
Jun 30, 2026
AWM INVESTMENT COMPANY, INC.
CIK 1535264
Shares
333.40K
Value
446.76K
Filed
Sep 30, 2024
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP
CIK 1164508
Shares
332.97K
Value
735.86K
Filed
Jun 30, 2026
MONIMUS CAPITAL MANAGEMENT, LP
CIK 1848831
Shares
310.91K
Value
901.63K
Filed
Jun 30, 2025
| # | Institution | CIK | Shares | Est. Value | Period |
|---|---|---|---|---|---|
| 1 | GSK PLC | 1131399 | 9.19M | 20.31M | Jun 30, 2026 |
| 2 | PFIZER INC | 78003 | 2.36M | 5.34M | Jun 30, 2026 |
| 3 | VANGUARD GROUP INC | 102909 | 2.08M | 4.85M | Dec 31, 2025 |
| 4 | VANGUARD CAPITAL MANAGEMENT LLC | 2100119 | 2.04M | 4.50M | Jun 30, 2026 |
| 5 | ATLAS VENTURE ASSOCIATES IX, LLC | 1671207 | 1.35M | 1.64M | Sep 30, 2023 |
| 6 | RENAISSANCE TECHNOLOGIES LLC | 1037389 | 947.90K | 2.09M | Jun 30, 2026 |
| 7 | ALPHABET INC. | 1652044 | 889.98K | 1.97M | Jun 30, 2026 |
| 8 | MURCHINSON LTD. | 1838556 | 873.91K | 629.22K | Mar 31, 2025 |
| 9 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 1446194 | 807.59K | 1.78M | Jun 30, 2026 |
| 10 | BLACKROCK, INC. | 2012383 | 594.40K | 1.31M | Jun 30, 2026 |
| 11 | GEODE CAPITAL MANAGEMENT, LLC | 1214717 | 566.33K | 1.25M | Jun 30, 2026 |
| 12 | RAYMOND JAMES FINANCIAL INC | 720005 | 521.71K | 1.15M | Jun 30, 2026 |
| 13 | BLACKROCK FINANCE, INC. | 1364742 | 483.40K | 628.42K | Jun 30, 2024 |
| 14 | NOVO HOLDINGS A/S | 1388325 | 468.90K | 628.33K | Sep 30, 2024 |
| 15 | ANSON FUNDS MANAGEMENT LP | 1491072 | 421.96K | 987.38K | Mar 31, 2026 |
| 16 | AMERIPRISE FINANCIAL INC | 820027 | 402.96K | 592.36K | Dec 31, 2023 |
| 17 | TWO SIGMA INVESTMENTS, LP | 1179392 | 382.81K | 846.02K | Jun 30, 2026 |
| 18 | AWM INVESTMENT COMPANY, INC. | 1535264 | 333.40K | 446.76K | Sep 30, 2024 |
| 19 | ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | 1164508 | 332.97K | 735.86K | Jun 30, 2026 |
| 20 | MONIMUS CAPITAL MANAGEMENT, LP | 1848831 | 310.91K | 901.63K | Jun 30, 2025 |
Data sourced from SEC Form 13F institutional holdings reports. Positions reflect the most recent filing per institution.