Sutro Biopharma (STRO)
Develops site-specific and dual-payload antibody-drug conjugates for oncology using cell-free protein synthesis.
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13F · 13D/G · Form 4
| Institutions | ≈ 99.69% | 16.53M shares | |
|---|---|---|---|
| 101 holders · as of Jun 30, 2026 · largest filers plus last quarter's tail | |||
| Insiders | 0.77% | 127.2K shares | |
| 11 holders · as of Sep 22, 2026 | |||
| Adds to | 100.46% | ||
16.58M company shares as of Sep 23, 2026 · institutions as of Jun 30, 2026 · holders as of their latest filing
Two share counts disagree (16.58M in the company's Sep 23, 2026 report, 9.68M elsewhere); stakes use the report.
This quarter's institutional total failed a plausibility check; shown: the largest filers plus last quarter's remainder.
These groups come from separate filings that can overlap, so they add to 100.46%; nothing is left for Other.
13F, as of Jun 30, 2026
101 holders · 16.53M shares · 44 new positions · 68 increased · 17 reduced · 15 closed
| Holder | Shares | % outstanding | Chg q/q | Filed |
|---|---|---|---|---|
| Perceptive Advisors LLC | 1.30M | 7.87% | +589.5K | Aug 14, 2026 |
| BVF Inc/IL | 1.25M | 7.55% | 0 | Aug 14, 2026 |
| Affinity Asset Advisors, LLC | 1.17M | 7.07% | +103.0K | Aug 13, 2026 |
| BlackRock, Inc. | 1.12M | 6.77% | +890.0K | Aug 7, 2026 |
| Samsara Biocapital, LLC | 1.06M | 6.41% | 0 | Aug 14, 2026 |
| Kynam Capital Management, LP | 872.6K | 5.26% | 0 | Aug 14, 2026 |
| Orbimed Advisors LLC | 743.9K | 4.49% | −57.2K | Aug 14, 2026 |
| Balyasny Asset Management L.P. | 711.2K | 4.29% | +245.4K | Aug 14, 2026 |
13D/G · 5% or more, as filed
| Holder | % of class | Shares | Form | Filed |
|---|---|---|---|---|
| Affinity Healthcare Fund, LP | 7.77% | 13G | Oct 23, 2025 | |
| Affinity Asset Advisors, LLC | 6.50% | 1.07M | 13G | May 14, 2026 |
| BlackRock, Inc. | 6.40% | 1.07M | 13G | Jul 30, 2026 |
| Point72 Asset Management, L.P. | 5.70% | 946.8K | 13G | May 1, 2026 |
| Millennium Management LLC | 5.60% | 13G | Jun 30, 2025 | |
| Perceptive Advisors LLC | 5.40% | 898.0K | 13G | Apr 21, 2026 |
| Kynam Capital Management, LP | 5.27% | 0 | 13G | May 15, 2026 |
Form 4
Latest trades
| Date | Insider | Type | Shares | Avg price | Owned after |
|---|---|---|---|---|---|
| Oct 15, 2025 | David Paulingofficer: Chief Admin. Ofcr. & GC | Purchase | 12,504 | $0.7992 | 71,737 |
| Oct 15, 2025 | Connie Matsuidirector | Purchase | 50,000 | $0.7990 | 50,000 |
| Oct 15, 2025 | Jane Chungdirector, officer: Chief Executive Officer | Purchase | 12,500 | $0.8009 | 122,850 |
| Oct 15, 2025 | Gregory K. Chowofficer: CFO | Purchase | 19,750 | $0.8100 | 19,750 |
| Oct 15, 2025 | Hans-Peter Gerberofficer: CHIEF SCIENTIFIC OFFICER | Purchase | 17,000 | $0.8004 | 71,832 |
House and Senate disclosures
Not reported.