Companies / Spero Therapeutics, Inc.
Spero Therapeutics, Inc.
Nasdaq: SPROCIK 1701108CAMBRIDGE, MA
Financials · FY2025
Ownership
58.2M shares outstanding · as of Aug 7, 2026
Ownership
| Insiders | 3.48% | 2,026,051 |
| Institutions | 37.56% | 21,874,275 |
| Public float | 58.96% | 34,334,501 |
% of common shares outstanding (exact, from the latest cover-page filing). Institutions are quarterly 13F snapshots; insiders reflect current officers & directors.
Insiders 5
View all →| Insider | % of shares | Shares |
|---|---|---|
Rajavelu EstherSee Remarks | 1.74% | 1,012,091 |
Keutzer TimothyChief Operating Officer | 1.28% | 742,506 |
Deshpande MilindDirector | 0.17% | 101,454 |
Pottage John C JrDirector | 0.15% | 85,000 |
Thomas Frank EDirector | 0.15% | 85,000 |
Institutional holders 58
View all →| Holder | Value | % of shares |
|---|---|---|
| $21.51M | 15.78% | |
| $5.50M | 4.06% | |
| $4.85M | 3.58% | |
| $2.78M | 2.04% | |
| $2.07M | 1.52% | |
| $1.97M | 1.53% | |
| $1.46M | 1.07% | |
| $1.31M | 1.02% | |
| $1.22M | 0.89% | |
| $927.0K | 0.68% |
Activity
Jun 30, 2026View all →
InsidersInstitutions
Who's accumulating and trimming this stock (13F).| Date | Actor | Action | Security | Value | Shares Δ | Position after | Impact |
|---|---|---|---|---|---|---|---|
| Q1 2026 as of | Two Sigma Investments, LP 13F manager | Add | Common Stock | $1.20M | +513K +137.71% | 885,631 1.52% of shares | low |
| Q1 2026 as of | Marshall Wace, LLP 13F manager | New | Common Stock | $367.5K | +157K | 157,072 0.27% of shares | low |
| Q2 2026 as of | BlackRock, Inc. 13F manager | Add | Common Stock | $355.3K | +161K +37.08% | 594,404 1.02% of shares | low |
| Q1 2026 as of | OMERS Administration Corporation 13F manager | Trim | Common Stock | $-214.6K | -92K -69.95% | 39,400 0.07% of shares | low |
| Q1 2026 as of | Renaissance Technologies LLC 13F manager | Trim | Common Stock | $-211.3K | -90K -7.06% | 1,189,235 2.04% of shares | low |
| Q2 2026 as of | Quadrature Capital Ltd 13F manager | Exit | Common Stock | $-88.1K | -38K -100.00% | — | low |
| Q1 2026 as of | Millennium Management LLC 13F manager | Exit | Common Stock | $-56.2K | -24K -100.00% | — | low |
| Q1 2026 as of | Texas Yale Capital Corp. 13F manager | Exit | Common Stock | $-23.3K | -10K -100.00% | — | low |
Securities
via CUSIP / OpenFIGI
| Symbol | Type | CUSIP |
|---|---|---|
| SPRO | Common Stock | 84833T103 |