SUTRO BIOPHARMA, INC.
STRO · Biological Products, (No Diagnostic Substances) · 16.6M shares · -38%/yr ↓ buyback · EDGAR filings ↗
Net buyback after stock comp: -$25M (gross $7K, SBC $25M)
Reference price $0.80 · est. market cap ~$13M — last insider purchase, 2025-10-15 (estimated from the dated SEC Form 4 price × shares outstanding — not a live quote)
Grade
D44Clinical/early-stage biotech — ADC biotech, heavy losses, funded.
Strengths
- Liquidity — current ratio 2.0 (27th)
Risks
- Pre-revenue, deep losses — per metrics
- Pre-revenue/clinical-stage — history of losses & need for capital per risk factors
- Binary clinical & funding risk — per 10-K
Notable findings
- Net lossNet loss (net margin -186.5%)
- Fund exitedNotable fund(s) exited this quarter: VANGUARD GROUP INC
- Strong balance sheetStrong balance sheet — $141M cash & investments
- Buying back stockNet buyback — share count -38%/yr over 3y
- Notable holderHeld by 5 notable fund(s): CITADEL ADVISORS LLC, RENAISSANCE TECHNOLOGIES LLC, STATE STREET CORP +2 more (as of 2026-03-31)
Quarterly revenue
Last 4 quarters · from SEC filings.
Key metrics
Operating margin
-154.5%
Net margin
-186.5%
Return on equity
144.3%
Return on assets
-109.9%
Revenue growth (QoQ)
24.7%
Current ratio
2.0×
EBITDA
-$151M
Tangible book value
-$132M
Cash & investments
$141M
Stock comp / revenue
13.7%
Insider transactions · last 18 months
| Date | Insider | Type | Shares | Price |
|---|---|---|---|---|
| 2026-06-02 | Chow Gregory K. | Option exercise | 2.5K | — |
| 2026-03-04 | Chung Jane | Tax withheld | 282 | $21.31 |
| 2026-03-04 | Pauling David | Option exercise | 675 | — |
| 2026-03-04 | Pauling David | Tax withheld | 277 | $21.31 |
| 2026-03-04 | Chung Jane | Option exercise | 788 | — |
| 2026-03-02 | Chung Jane | Option exercise | 7.8K | — |
| 2026-03-02 | Pauling David | Option exercise | 2.4K | — |
| 2026-03-02 | Pauling David | Tax withheld | 970 | $20.55 |
| 2026-03-02 | Gerber Hans-Peter | Option exercise | 2.8K | — |
| 2026-03-02 | Gerber Hans-Peter | Tax withheld | 1.2K | $20.55 |
| 2026-03-02 | Chung Jane | Tax withheld | 2.8K | $20.55 |
| 2026-03-01 | Gerber Hans-Peter | Option exercise | 1.1K | — |
| 2026-03-01 | Gerber Hans-Peter | Tax withheld | 463 | $20.47 |
| 2026-03-01 | Chung Jane | Option exercise | 2.5K | — |
| 2026-03-01 | Pauling David | Option exercise | 500 | — |
| 2026-03-01 | Pauling David | Option exercise | 842 | — |
| 2026-03-01 | Pauling David | Tax withheld | 551 | $20.47 |
| 2026-03-01 | Chung Jane | Tax withheld | 1.3K | $20.47 |
| 2026-03-01 | Chung Jane | Option exercise | 688 | — |
| 2025-12-12 | Chung Jane | Option exercise | 2.5K | — |
| 2025-12-12 | Chung Jane | Tax withheld | 894 | $8.02 |
| 2025-10-15 | Chow Gregory K. | Buy | 20K | $0.81 |
| 2025-10-15 | Pauling David | Buy | 13K | $0.80 |
| 2025-10-15 | Gerber Hans-Peter | Buy | 17K | $0.80 |
| 2025-10-15 | Chung Jane | Buy | 12K | $0.80 |
| 2025-10-15 | MATSUI CONNIE | Buy | 50K | $0.80 |
| 2025-09-18 | Gerber Hans-Peter | Option exercise | 38K | — |
| 2025-09-18 | Gerber Hans-Peter | Tax withheld | 13K | $0.90 |
| 2025-08-09 | Chung Jane | Option exercise | 19K | — |
| 2025-08-09 | Chung Jane | Tax withheld | 6.7K | $0.80 |
| 2025-07-08 | Leyman Barbara | Tax withheld | 8.9K | $0.78 |
| 2025-07-08 | Leyman Barbara | Option exercise | 25K | — |
| 2025-05-15 | ALBINI EDWARD C | Option exercise | 9.1K | — |
| 2025-05-15 | ALBINI EDWARD C | Option exercise | 24K | — |
| 2025-05-15 | ALBINI EDWARD C | Option exercise | 11K | — |
| 2025-05-15 | ALBINI EDWARD C | Tax withheld | 16K | $0.88 |
| 2025-05-01 | FITZPATRICK LINDA A | Tax withheld | 14K | $1.07 |
| 2025-05-01 | FITZPATRICK LINDA A | Option exercise | 9.1K | — |
| 2025-05-01 | FITZPATRICK LINDA A | Option exercise | 9.7K | — |
| 2025-05-01 | FITZPATRICK LINDA A | Option exercise | 13K | — |
| 2025-05-01 | FITZPATRICK LINDA A | Option exercise | 5.8K | — |
| 2025-05-01 | Srinivasan Venkatesh | Option exercise | 2.5K | — |
| 2025-05-01 | Srinivasan Venkatesh | Tax withheld | 894 | $1.07 |
| 2025-05-01 | Borgman Anne Elizabeth | Option exercise | 53K | — |
| 2025-05-01 | Borgman Anne Elizabeth | Option exercise | 16K | — |
| 2025-05-01 | Borgman Anne Elizabeth | Tax withheld | 25K | $1.07 |
| 2025-04-11 | Srinivasan Venkatesh | Tax withheld | 7.6K | $0.60 |
| 2025-04-11 | Srinivasan Venkatesh | Option exercise | 21K | — |
| 2025-03-05 | FITZPATRICK LINDA A | Tax withheld | 3.6K | $1.36 |
| 2025-03-05 | ALBINI EDWARD C | Option exercise | 8.8K | — |
| 2025-03-05 | ALBINI EDWARD C | Tax withheld | 3.6K | $1.36 |
| 2025-03-05 | NEWELL WILLIAM J | Tax withheld | 6.7K | $1.36 |
| 2025-03-05 | FITZPATRICK LINDA A | Option exercise | 8.8K | — |
| 2025-03-05 | NEWELL WILLIAM J | Option exercise | 19K | — |
| 2025-03-04 | FITZPATRICK LINDA A | Tax withheld | 3.7K | $1.42 |
| 2025-03-04 | NEWELL WILLIAM J | Option exercise | 31K | — |
| 2025-03-04 | NEWELL WILLIAM J | Tax withheld | 11K | $1.42 |
| 2025-03-04 | Chung Jane | Option exercise | 7.9K | — |
| 2025-03-04 | Chung Jane | Tax withheld | 2.3K | $1.42 |
| 2025-03-04 | ALBINI EDWARD C | Tax withheld | 3.7K | $1.42 |
| 2025-03-04 | ALBINI EDWARD C | Option exercise | 9.1K | — |
| 2025-03-04 | FITZPATRICK LINDA A | Option exercise | 9.1K | — |
| 2025-03-01 | Srinivasan Venkatesh | Option exercise | 6.4K | — |
| 2025-03-01 | Srinivasan Venkatesh | Tax withheld | 4.7K | $1.59 |
| 2025-03-01 | Borgman Anne Elizabeth | Option exercise | 11K | — |
| 2025-03-01 | ALBINI EDWARD C | Option exercise | 7.9K | — |
| 2025-03-01 | ALBINI EDWARD C | Option exercise | 17K | — |
| 2025-03-01 | ALBINI EDWARD C | Tax withheld | 10K | $1.59 |
| 2025-03-01 | Chung Jane | Option exercise | 6.9K | — |
| 2025-03-01 | Chung Jane | Option exercise | 25K | — |
| 2025-03-01 | Chung Jane | Tax withheld | 9.4K | $1.59 |
| 2025-03-01 | FITZPATRICK LINDA A | Option exercise | 6.9K | — |
| 2025-03-01 | FITZPATRICK LINDA A | Option exercise | 13K | — |
| 2025-03-01 | FITZPATRICK LINDA A | Tax withheld | 8.3K | $1.59 |
| 2025-03-01 | Gerber Hans-Peter | Option exercise | 11K | — |
| 2025-03-01 | Gerber Hans-Peter | Tax withheld | 4.6K | $1.59 |
| 2025-03-01 | NEWELL WILLIAM J | Option exercise | 24K | — |
| 2025-03-01 | NEWELL WILLIAM J | Option exercise | 42K | — |
| 2025-03-01 | NEWELL WILLIAM J | Tax withheld | 25K | $1.59 |
| 2025-03-01 | Srinivasan Venkatesh | Option exercise | 5.0K | — |
| 2025-03-01 | Borgman Anne Elizabeth | Tax withheld | 4.6K | $1.59 |
| 2025-02-28 | Borgman Anne Elizabeth | Tax withheld | 15K | $1.59 |
| 2025-02-28 | Borgman Anne Elizabeth | Option exercise | 38K | — |
All non-derivative Form 4 activity (SEC), newest first.
Clinical trials
| Trial | Title | Phase | Status | Primary completion |
|---|---|---|---|---|
| NCT07227168 ↗ | A Study of STRO-004 in Adults With Refractory/Recurrent Metastatic Cancer Head and Neck Squamous Cell Carcinoma HNSCC, Non-Small Cell Lung Cancer NSCLC | PHASE1 | Recruiting | 2027-12-01 |
| NCT05870748 ↗ | REFRaME-O1: A Study to Investigate the Efficacy and Safety of Luveltamab Tazevibulin Versus Investigator's Choice (IC) Chemotherapy in Women With Ovarian Cancer (Including Fallopian Tube or Primary Peritoneal Cancers) Expressing FOLR1 Ovarian Cancer, Epithelial Ovarian Cancer | PHASE2/PHASE3 | Terminated | 2025-08-26 |
| NCT06679582 ↗ | Luveltamab Tazevibulin (STRO-002) in Infants and Children < 12 Years of Age With Relapsed/Refractory CBFA2T3::GLIS2 AML Acute Myeloid Leukemia (AML) | PHASE1/PHASE2 | Terminated | 2025-06-01 |
| NCT05200364 ↗ | A Study of STRO-002, an Anti-Folate Receptor Alpha Antibody Drug Conjugate, in Combination With Bevacizumab in Epithelial Ovarian Cancer Ovarian Cancer, Ovarian Carcinoma | PHASE1 | Terminated | 2025-06-01 |
| NCT06555263 ↗ | Study to Investigate Luveltamab Tazevibulin in Adults With Advanced or Metastatic Non-small Cell Lung Cancer Lung Cancer, Lung Cancer Metastatic | PHASE2 | Withdrawn | 2025-05-01 |
| NCT03748186 ↗ | Study of STRO-002, an Anti-Folate Receptor Alpha (FolRα) Antibody Drug Conjugate in Ovarian & Endometrial Cancers Ovarian Cancer, Ovarian Carcinoma | PHASE1 | Completed | 2024-06-04 |
| NCT03424603 ↗ | Study of STRO-001, an Anti-CD74 Antibody Drug Conjugate, in Patients With Advanced B-Cell Malignancies B-cell Lymphoma, Non Hodgkin Lymphoma | PHASE1 | Completed | 2024-02-15 |
Source: ClinicalTrials.gov (U.S. NIH) · active studies first.
Notable events (8-K)
Recent filings
| Form | Filed | Period | Accession |
|---|---|---|---|
| 8-K | 2026-06-08 | 2026-06-05 | 0001193125-26-261658 ↗ |
| 10-Q | 2026-05-14 | 2026-03-31 | 0001193125-26-224170 ↗ |
| 8-K | 2026-05-14 | 2026-05-14 | 0001193125-26-224065 ↗ |
| 10-K | 2026-03-23 | 2025-12-31 | 0001193125-26-119873 ↗ |
| 8-K | 2026-03-23 | 2026-03-23 | 0001193125-26-119844 ↗ |
| 8-K | 2026-02-10 | 2026-02-09 | 0001193125-26-044934 ↗ |
| 8-K | 2025-12-17 | 2025-12-17 | 0001193125-25-322859 ↗ |
| 8-K | 2025-12-03 | 2025-12-01 | 0001193125-25-306786 ↗ |
| 8-K | 2025-11-06 | 2025-11-06 | 0001193125-25-269833 ↗ |
| 10-Q | 2025-11-06 | 2025-09-30 | 0001193125-25-270036 ↗ |
| 8-K | 2025-09-29 | 2025-09-29 | 0001193125-25-223434 ↗ |
| 10-Q | 2025-08-07 | 2025-06-30 | 0000950170-25-105219 ↗ |