Sutro Biopharma, Inc. (STRO) shareholders
STRONasdaqBiological Products, (No Diagnostic Substances)Fiscal year ends December 31
$10.26+0.09 (+0.88%)
Close on Nov 11, 2026Market cap $170.12MP/E –Yield –
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
99.4%
16M of 17M shares
Institutional holders
100
40 new, 17 sold out
Net institutional buying
2M
In Q2 2026
Insider trades, 12 months
0 buys · 0 sales
Open-market trades only
Shares held by institutions
Holders of more than 5%
Latest Schedule 13D (active) or 13G (passive) filed by each holder
| Holder | Shares | % of class | Filing | As of |
|---|---|---|---|---|
| Affinity Healthcare Fund, LP Joint filing with Affinity Asset Advisors, LLC (7.77%) | 6,583,772 | 7.77% | 13G (passive) | Oct 16, 2025 |
| Millennium Group Management LLC Joint filing with Millennium Management LLC (5.60%), Israel A. Englander (5.60%) | 4,717,215 | 5.60% | 13G (passive) | Jun 27, 2025 |
| Adage Capital Partners, L.P. Joint filing with Adage Capital Partners GP, L.L.C. (7.33%), Adage Capital Management, L.P. (7.33%) and 2 more | 4,467,796 | 7.33% | 13G (passive) amendment | Dec 31, 2023 |
| RA Capital Healthcare Fund, L.P. Joint filing with RA Capital Management, L.P. (5.30%), Peter Kolchinsky (5.30%) and 1 more | 4,434,637 | 5.30% | 13G (passive) | Mar 28, 2025 |
| Joseph Edelman Joint filing with Perceptive Advisors LLC (7.90%), Perceptive Life Sciences Master Fund, Ltd. (7.90%) | 1,304,846 | 7.90% | 13G (passive) amendment | Jun 30, 2026 |
| Lampert Mark N Joint filing with Bvf Partners L P/Il (7.60%), Bvf Inc/Il (7.60%) and 1 more | 1,251,788 | 7.60% | 13G (passive) | Feb 10, 2026 |
| Affinity Asset Advisors, LLC Joint filing with Michael Cho (6.50%) | 1,069,519 | 6.50% | 13G (passive) amendment | Mar 31, 2026 |
| BlackRock, Inc. | 1,065,366 | 6.40% | 13G (passive) | Jun 30, 2026 |
| Srinivas Akkaraju | 1,062,872 | 6.40% | 13G (passive) | Feb 11, 2026 |
| Point72 Asset Management, L.P. Joint filing with Point72 Capital Advisors, Inc. (5.70%), Steven A. Cohen (5.70%) | 946,829 | 5.70% | 13G (passive) | Apr 24, 2026 |
| Perceptive Advisors LLC Joint filing with Joseph Edelman (5.40%), Perceptive Life Sciences Master Fund, Ltd. (5.40%) | 898,025 | 5.40% | 13G (passive) | Apr 14, 2026 |
| Coastlands Capital LLC Joint filing with Coastlands Capital LP (5.14%), Coastlands Capital Partners LP (5.14%) and 2 more | 852,669 | 5.14% | 13G (passive) | Nov 5, 2026 |
| Michael Cho Joint filing with Affinity Asset Advisors, LLC (8.80%) | 748,382 | 8.80% | 13G (passive) amendment | Jan 22, 2026 |
| Yue Tang Joint filing with Kynam Capital Management, LP (5.27%), Kynam Capital Management GP, LLC (5.27%) | 0 | 5.27% | 13G (passive) amendment | Mar 31, 2026 |
| Kynam Capital Management, LP Joint filing with Kynam Capital Management GP, LLC (6.44%), Yue Tang (6.44%) | 0 | 6.44% | 13G (passive) | Mar 31, 2025 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of STRO | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| Perceptive Advisors LLC | 1,304,846 | 7.87% | $43.32M | +589,539 | 0.65% |
| Bvf Inc/Il | 1,251,788 | 7.55% | $41.56M | – | 1.06% |
| Affinity Asset Advisors, LLC | 1,172,487 | 7.07% | $38.93M | +102,968 | 1.76% |
| BlackRock, Inc. | 1,122,655 | 6.77% | $37.27M | +889,971 | 0.00% |
| Samsara BioCapital, LLC | 1,062,872 | 6.41% | $35.29M | – | 2.90% |
| Kynam Capital Management, LP | 872,558 | 5.26% | $28.97M | – | 1.60% |
| Orbimed Advisors LLC | 743,944 | 4.49% | $24.70M | −57,200 | 0.46% |
| Balyasny Asset Management L.P. | 711,162 | 4.29% | $23.61M | +245,370 | 0.03% |
| Vanguard Capital Management LLC | 694,219 | 4.19% | $23.05M | −26,223 | 0.00% |
| Eventide Asset Management, LLC | 585,262 | 3.53% | $19.43M | −130,045 | 0.26% |
| Velan Capital Investment Management LP | 512,160 | 3.09% | $17.00M | – | 10.36% |
| Woodline Partners LP | 458,029 | 2.76% | $15.21M | +588 | 0.05% |
| ADAR1 Capital Management, LLC | 404,014 | 2.44% | $13.41M | −120,427 | 0.61% |
| Geode Capital Management, LLC | 389,692 | 2.35% | $12.94M | +218,306 | 0.00% |
| Acadian Asset Management LLC | 373,839 | 2.25% | $12.41M | +38,026 | 0.01% |
| Millennium Management LLC | 365,972 | 2.21% | $12.15M | +155,594 | 0.00% |
| State Street Corp | 305,979 | 1.85% | $10.16M | +253,861 | 0.00% |
| Merck & Co., Inc. | 272,351 | 1.64% | $9.04M | – | 1.72% |
| Acuta Capital Partners, LLC | 270,251 | 1.63% | $8.97M | +826 | 6.25% |
| Ameriprise Financial Inc | 244,669 | 1.48% | $8.12M | New | 0.00% |
Institutional buying and selling by quarter
Positions opened, added to, reduced and closed by 13F filers
| Quarter | Holders | Shares held | % of shares | New / added | Reduced / closed | Shares bought | Shares sold |
|---|---|---|---|---|---|---|---|
| Q2 2026 | 100 | 16M | 99.4% | 40 / 24 | 18 / 17 | 5M | 3M |
| Q1 2026 | 78 | 14M | 86.9% | 26 / 23 | 14 / 9 | 10M | 1M |
| Q4 2025 | 63 | 6M | 33.9% | 11 / 15 | 26 / 33 | 2M | 1M |
| Q3 2025 | 88 | 5M | 32.2% | 10 / 19 | 34 / 23 | 0M | 1M |
| Q2 2025 | 101 | 6M | 33.6% | 31 / 23 | 23 / 43 | 1M | 2M |
| Q1 2025 | 113 | 6M | 37.1% | 18 / 38 | 32 / 27 | 1M | 2M |
| Q4 2024 | 123 | 6M | 38.5% | 24 / 40 | 36 / 30 | 1M | 1M |
| Q3 2024 | 130 | 6M | 37.7% | 24 / 50 | 31 / 11 | 1M | 1M |
| Q2 2024 | 119 | 6M | 38.1% | 21 / 58 | 28 / 19 | 1M | 1M |
| Q1 2024 | 117 | 5M | 32.9% | 20 / 49 | 32 / 17 | 1M | 2M |
| Q4 2023 | 114 | 6M | 33.7% | 21 / 44 | 28 / 15 | 1M | 1M |
| Q3 2023 | 108 | 6M | 33.7% | 7 / 43 | 32 / 18 | 0M | 0M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
72 funds held STRO in Q2 2026, 54% of their shares through ETFs. Each fund counts once per quarter, from its quarter-end report.
| Fund | Shares | % of STRO | Value | % of fund | As of |
|---|---|---|---|---|---|
| Eventide Healthcare & Life Sciences Fund | 585,262 | 3.53% | $19.43M | 1.09% | Jun 30, 2026 |
| Vanguard Total Stock Market Index Fund | 501,524 | 3.02% | $16.65M | 0.00% | Jun 30, 2026 |
| iShares Russell 2000 ETF | 326,271 | 1.97% | $10.83M | 0.01% | Jun 30, 2026 |
| Vanguard Extended Market Index Fund | 177,208 | 1.07% | $5.88M | 0.01% | Jun 30, 2026 |
| Fidelity Small Cap Index Fund | 173,722 | 1.05% | $4.20M | 0.01% | Jul 31, 2026 |
| Nuveen Quant Small Cap Equity Fund | 126,290 | 0.76% | $3.05M | 0.08% | Jul 31, 2026 |
| iShares Russell 2000 Value ETF | 98,529 | 0.59% | $3.27M | 0.02% | Jun 30, 2026 |
| Fidelity Extended Market Index Fund | 78,053 | 0.47% | $2.28M | 0.01% | May 31, 2026 |
| Goldman Sachs Small Cap Equity Insights Fund | 77,195 | 0.47% | $1.87M | 0.18% | Jul 31, 2026 |
| Goldman Sachs Small Cap Value Insights Fund | 66,530 | 0.40% | $1.61M | 0.12% | Jul 31, 2026 |
| JPMorgan U.S. Small Company Fund | 60,304 | 0.36% | $2.00M | 0.18% | Jun 30, 2026 |
| iShares Micro-Cap ETF | 47,714 | 0.29% | $1.58M | 0.10% | Jun 30, 2026 |
| Schwab Small-Cap Index Fund | 38,737 | 0.23% | $936.27K | 0.01% | Jul 31, 2026 |
| Vanguard Explorer Fund | 28,467 | 0.17% | $688.05K | 0.00% | Jul 31, 2026 |
| Schwab Small-Cap Equity Fund | 28,234 | 0.17% | $682.42K | 0.10% | Jul 31, 2026 |
Officers, directors and major owners
People who filed Forms 3, 4 or 5 in the last two years
| Name | Role | Shares owned | % of shares | Latest filing |
|---|---|---|---|---|
| Jane Chung | Chief Executive Officer, Director | 21,567 | 0.13% | Mar 6, 2026 |
| William J. Newell | CEO, Director | 409,056 | 2.47% | Mar 7, 2025 |
| Hans-Peter Gerber | CHIEF SCIENTIFIC OFFICER | 12,367 | 0.07% | Sep 22, 2026 |
| Gregory K. Chow | CFO | 4,725 | 0.03% | Jun 2, 2026 |
| David Pauling | Chief Admin. Ofcr. & GC | 10,025 | 0.06% | Mar 6, 2026 |
| Barbara Leyman | Chief Business Officer | 16,056 | 0.10% | Aug 26, 2025 |
| Edward C. Albini | CFO AND SECRETARY | 176,800 | 1.07% | May 19, 2025 |
| Venkatesh Srinivasan | CHIEF TECH OP OFFICER | 53,686 | 0.32% | May 5, 2025 |
| Linda A. Fitzpatrick | CHIEF PEOPLE & COMM. OFFICER | 137,821 | 0.83% | May 5, 2025 |
| Anne Elizabeth Borgman | CHIEF MEDICAL OFFICER | 97,452 | 0.59% | May 5, 2025 |
| Sukhi Jagpal | Director | – | – | Jun 9, 2026 |
| Joseph M. Lobacki | Director | 0 | – | Jun 9, 2026 |
| Connie Matsui | Director | 50,000 | 0.30% | Jun 9, 2026 |
| Jon Marc Wigginton | Director | 0 | – | Jun 9, 2026 |
| Daniel H. Petree | Director | 22,457 | 0.14% | Jun 9, 2026 |
| Michael Dybbs | Director | 0 | – | Jun 9, 2026 |
| James P. Panek | Director | 0 | – | Jun 9, 2026 |
| Heidi Hunter | Director | 0 | – | Jun 9, 2026 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Hans-Peter Gerber CHIEF SCIENTIFIC OFFICER | Sep 18, 2026 | Tax withholding | −1,345 | $15.34 | $20.63K | 12,367 |
| Hans-Peter Gerber CHIEF SCIENTIFIC OFFICER | Sep 18, 2026 | Option exercise | +3,750 | – | – | 13,712 |
| Gregory K. Chow CFO | Jun 2, 2026 | Option exercise | +2,500 | – | – | 4,725 |
| Jane Chung Chief Executive Officer, Director | Mar 4, 2026 | Option exercise | +788 | – | – | 21,567 |
| Jane Chung Chief Executive Officer, Director | Mar 4, 2026 | Tax withholding | −282 | $21.31 | $6.01K | 21,285 |
| David Pauling Chief Admin. Ofcr. & GC | Mar 4, 2026 | Option exercise | +675 | – | – | 10,025 |
| David Pauling Chief Admin. Ofcr. & GC | Mar 4, 2026 | Tax withholding | −277 | $21.31 | $5.90K | 9,748 |
| Hans-Peter Gerber CHIEF SCIENTIFIC OFFICER | Mar 2, 2026 | Tax withholding | −1,170 | $20.55 | $24.04K | 9,518 |
| Hans-Peter Gerber CHIEF SCIENTIFIC OFFICER | Mar 2, 2026 | Option exercise | +2,843 | – | – | 10,688 |
| Jane Chung Chief Executive Officer, Director | Mar 2, 2026 | Option exercise | +7,750 | – | – | 23,558 |
| Jane Chung Chief Executive Officer, Director | Mar 2, 2026 | Tax withholding | −2,779 | $20.55 | $57.11K | 20,779 |
| David Pauling Chief Admin. Ofcr. & GC | Mar 2, 2026 | Option exercise | +2,356 | – | – | 10,320 |
| David Pauling Chief Admin. Ofcr. & GC | Mar 2, 2026 | Tax withholding | −970 | $20.55 | $19.93K | 9,350 |
| Hans-Peter Gerber CHIEF SCIENTIFIC OFFICER | Mar 1, 2026 | Option exercise | +1,125 | – | – | 8,308 |
| Hans-Peter Gerber CHIEF SCIENTIFIC OFFICER | Mar 1, 2026 | Tax withholding | −463 | $20.47 | $9.48K | 7,845 |
| Jane Chung Chief Executive Officer, Director | Mar 1, 2026 | Option exercise | +688 | – | – | 14,579 |
| Jane Chung Chief Executive Officer, Director | Mar 1, 2026 | Option exercise | +2,500 | – | – | 17,079 |
| Jane Chung Chief Executive Officer, Director | Mar 1, 2026 | Tax withholding | −1,271 | $20.47 | $26.02K | 15,808 |
| David Pauling Chief Admin. Ofcr. & GC | Mar 1, 2026 | Tax withholding | −551 | $20.47 | $11.28K | 7,964 |
| David Pauling Chief Admin. Ofcr. & GC | Mar 1, 2026 | Option exercise | +842 | – | – | 8,515 |
| David Pauling Chief Admin. Ofcr. & GC | Mar 1, 2026 | Option exercise | +500 | – | – | 7,673 |
| Jane Chung Chief Executive Officer, Director | Dec 12, 2025 | Option exercise | +2,500 | – | – | 14,785 |
| Jane Chung Chief Executive Officer, Director | Dec 12, 2025 | Tax withholding | −894 | $8.02 | $7.17K | 13,891 |
| Connie Matsui Director | Oct 15, 2025 | Buy | +50,000 | $0.80 | $40.00K | 50,000 |
| Gregory K. Chow CFO | Oct 15, 2025 | Buy | +19,750 | $0.81 | $16.00K | 19,750 |
| David Pauling Chief Admin. Ofcr. & GC | Oct 15, 2025 | Buy | +12,504 | $0.80 | $10.00K | 71,737 |
| Hans-Peter Gerber CHIEF SCIENTIFIC OFFICER | Oct 15, 2025 | Buy | +17,000 | $0.80 | $13.60K | 71,832 |
| Jane Chung Chief Executive Officer, Director | Oct 15, 2025 | Buy | +12,500 | $0.80 | $10.00K | 122,850 |
| Hans-Peter Gerber CHIEF SCIENTIFIC OFFICER | Sep 18, 2025 | Tax withholding | −13,417 | $0.90 | $12.08K | 54,832 |
| Hans-Peter Gerber CHIEF SCIENTIFIC OFFICER | Sep 18, 2025 | Option exercise | +37,500 | – | – | 68,249 |
| Jane Chung Chief Executive Officer, Director | Aug 9, 2025 | Tax withholding | −6,708 | $0.80 | $5.37K | 110,350 |
| Jane Chung Chief Executive Officer, Director | Aug 9, 2025 | Option exercise | +18,750 | – | – | 117,058 |
| Barbara Leyman Chief Business Officer | Jul 8, 2025 | Tax withholding | −8,944 | $0.78 | $6.98K | 16,056 |
| Barbara Leyman Chief Business Officer | Jul 8, 2025 | Option exercise | +25,000 | – | – | 25,000 |
| Edward C. Albini CFO AND SECRETARY | May 15, 2025 | Option exercise | +9,125 | – | – | 176,800 |
| Edward C. Albini CFO AND SECRETARY | May 15, 2025 | Option exercise | +11,156 | – | – | 167,675 |
| Edward C. Albini CFO AND SECRETARY | May 15, 2025 | Tax withholding | −15,995 | $0.88 | $14.08K | 160,805 |
| Edward C. Albini CFO AND SECRETARY | May 15, 2025 | Option exercise | +24,438 | – | – | 156,519 |
| Linda A. Fitzpatrick CHIEF PEOPLE & COMM. OFFICER | May 1, 2025 | Option exercise | +13,140 | – | – | 127,438 |
| Linda A. Fitzpatrick CHIEF PEOPLE & COMM. OFFICER | May 1, 2025 | Option exercise | +5,844 | – | – | 133,282 |
| Linda A. Fitzpatrick CHIEF PEOPLE & COMM. OFFICER | May 1, 2025 | Tax withholding | −13,538 | $1.07 | $14.49K | 119,744 |
| Linda A. Fitzpatrick CHIEF PEOPLE & COMM. OFFICER | May 1, 2025 | Option exercise | +9,740 | – | – | 114,298 |
| Linda A. Fitzpatrick CHIEF PEOPLE & COMM. OFFICER | May 1, 2025 | Option exercise | +9,125 | – | – | 104,558 |
| Venkatesh Srinivasan CHIEF TECH OP OFFICER | May 1, 2025 | Tax withholding | −894 | $1.07 | $957 | 53,686 |
| Venkatesh Srinivasan CHIEF TECH OP OFFICER | May 1, 2025 | Option exercise | +2,500 | – | – | 54,580 |
| Anne Elizabeth Borgman CHIEF MEDICAL OFFICER | May 1, 2025 | Tax withholding | −24,709 | $1.07 | $26.44K | 97,452 |
| Anne Elizabeth Borgman CHIEF MEDICAL OFFICER | May 1, 2025 | Option exercise | +53,125 | – | – | 106,223 |
| Anne Elizabeth Borgman CHIEF MEDICAL OFFICER | May 1, 2025 | Option exercise | +15,938 | – | – | 122,161 |
| Venkatesh Srinivasan CHIEF TECH OP OFFICER | Apr 11, 2025 | Tax withholding | −7,603 | $0.60 | $4.56K | 52,080 |
| Venkatesh Srinivasan CHIEF TECH OP OFFICER | Apr 11, 2025 | Option exercise | +21,250 | – | – | 59,683 |
| William J. Newell CEO, Director | Mar 5, 2025 | Tax withholding | −6,708 | $1.36 | $9.12K | 292,531 |
| William J. Newell CEO, Director | Mar 5, 2025 | Option exercise | +18,750 | – | – | 299,239 |
| Linda A. Fitzpatrick CHIEF PEOPLE & COMM. OFFICER | Mar 5, 2025 | Option exercise | +8,750 | – | – | 99,027 |
| Linda A. Fitzpatrick CHIEF PEOPLE & COMM. OFFICER | Mar 5, 2025 | Tax withholding | −3,594 | $1.36 | $4.89K | 95,433 |
| Edward C. Albini CFO AND SECRETARY | Mar 5, 2025 | Tax withholding | −3,594 | $1.36 | $4.89K | 132,081 |
| Edward C. Albini CFO AND SECRETARY | Mar 5, 2025 | Option exercise | +8,750 | – | – | 135,675 |
| Edward C. Albini CFO AND SECRETARY | Mar 4, 2025 | Option exercise | +9,125 | – | – | 130,673 |
| Edward C. Albini CFO AND SECRETARY | Mar 4, 2025 | Tax withholding | −3,748 | $1.42 | $5.32K | 126,925 |
| Jane Chung PRESIDENT AND COO | Mar 4, 2025 | Tax withholding | −2,334 | $1.42 | $3.31K | 98,308 |
| Jane Chung PRESIDENT AND COO | Mar 4, 2025 | Option exercise | +7,875 | – | – | 100,642 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.
Short interest
Shares sold short and not yet bought back, as of Oct 30, 2026 (FINRA, reported twice a month)
Short % of float
14.50%
2M shares short
Days to cover
6.3
At 0M shares a day
Change since last report
+15.1%
From 2M shares
Short volume, 20 days
46.7%
Of volume reported to FINRA
Shares sold short, last 12 months
Short sale volume counts trades marked short on any given day, including market-maker hedging, so it runs far higher than the share of Sutro Biopharma's stock actually held short. Settlement fails (shares not delivered on time) peaked at 192 shares on Aug 28, 2026 over the last 90 days.
Planned insider sales
Notices of proposed sale filed on Form 144 before shares are sold
| Seller | Filed | Shares | Market value | Planned sale | Acquired through |
|---|---|---|---|---|---|
| Barbara Leyman Former Officer | Jan 20, 2026 | 8,929 | $130.96K | Jan 20, 2026 | Stock Option Exercise |
| Nicki Vasquez Officer | Jan 29, 2024 | 12,185 | $60.93K | Jan 29, 2024 | Restricted Stock |
| Shtylla Brunilda Officer | Aug 25, 2023 | 27,041 | $156.33K | Aug 25, 2023 | RETAIL PURCHASE |
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