Korro Bio, Inc. (KRRO) shareholders
KRRONasdaqPharmaceutical PreparationsFiscal year ends December 31
$13.61−0.70 (-4.89%)
Close on Nov 13, 2026Market cap $200.42MP/E –Yield –
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
100.0%
15M of 15M shares
Institutional holders
107
21 new, 11 sold out
Net institutional buying
2M
In Q2 2026
Insider trades, 12 months
16 buys · 39 sales
Net bought $15.00M
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 |
|---|---|---|---|---|
| Lynx1 Capital Management LP Joint filing with Weston Nichols (10.70%) | 1,538,296 | 10.70% | 13G (passive) amendment | Mar 31, 2026 |
| Bong Y. Koh Joint filing with Venrock Healthcare Capital Partners III, L.P. (9.90%), VHCP Co-Investment Holdings III, LLC (9.90%) and 4 more | 1,488,685 | 9.90% | 13G (passive) | Mar 10, 2026 |
| Ali Behbahani Joint filing with New Enterprise Associates 17, L.P. (9.90%), NEA Partners 17, L.P. (9.90%) and 9 more | 1,456,677 | 9.90% | 13D (active) amendment | Mar 10, 2026 |
| Balyasny Asset Management Holdings LP Joint filing with Balyasny Asset Management L.P. (6.60%), Bam Gp LLC (6.60%) and 2 more | 951,783 | 6.60% | 13G (passive) amendment | Jun 30, 2026 |
| Steven A. Cohen | 816,885 | 5.70% | 13G (passive) | Mar 10, 2026 |
| Weston Nichols Joint filing with Lynx1 Capital Management LP (7.80%) | 733,633 | 7.80% | 13G (passive) | Dec 23, 2025 |
| Daniel Mack Joint filing with Nantahala Capital Management, LLC (6.37%), Wilmot B. Harkey (6.37%) | 600,000 | 6.37% | 13G (passive) | Dec 31, 2025 |
| Platanus Investment LLC Joint filing with Xinyi Cai (6.80%) | 540,165 | 6.80% | 13G (passive) | Nov 3, 2023 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of KRRO | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| Lynx1 Capital Management LP | 1,538,296 | 10.45% | $20.27M | – | 2.34% |
| Nantahala Capital Management, LLC | 1,320,072 | 8.96% | $17.40M | +660,036 | 0.29% |
| NEA Management Company, LLC | 1,297,893 | 8.81% | $17.11M | – | 1.08% |
| VR Adviser, LLC | 1,009,500 | 6.86% | $13.31M | – | 0.40% |
| Atlas Venture Life Science Advisors, LLC | 962,884 | 6.54% | $12.69M | −174,265 | 1.44% |
| Balyasny Asset Management L.P. | 951,783 | 6.46% | $12.54M | −88,271 | 0.02% |
| BlackRock, Inc. | 817,621 | 5.55% | $10.78M | +357,615 | 0.00% |
| Affinity Asset Advisors, LLC | 706,904 | 4.80% | $9.32M | – | 0.42% |
| Adage Capital Partners Gp, L.L.C. | 540,968 | 3.67% | $7.13M | +312,568 | 0.01% |
| ADAR1 Capital Management, LLC | 540,054 | 3.67% | $7.12M | – | 0.33% |
| Vanguard Capital Management LLC | 454,778 | 3.09% | $5.99M | +143,865 | 0.00% |
| Driehaus Capital Management LLC | 450,045 | 3.06% | $5.93M | – | 0.03% |
| TCG Crossover Management, LLC | 416,301 | 2.83% | $5.49M | – | 0.13% |
| Kalehua Capital Management LLC | 405,040 | 2.75% | $5.34M | +295,664 | 1.70% |
| Siren, L.L.C. | 347,718 | 2.36% | $4.58M | – | 0.09% |
| Aqr Capital Management LLC | 298,974 | 2.03% | $3.94M | +31,219 | 0.00% |
| Geode Capital Management, LLC | 296,870 | 2.02% | $3.91M | +123,227 | 0.00% |
| 72 Investment Holdings, LLC | 276,831 | 1.88% | $3.65M | – | 7.30% |
| State Street Corp | 232,587 | 1.58% | $3.07M | +92,246 | 0.00% |
| Vanguard Portfolio Management LLC | 223,551 | 1.52% | $2.95M | +74,992 | 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 | 107 | 15M | 100.0% | 21 / 48 | 19 / 11 | 3M | 1M |
| Q1 2026 | 99 | 13M | 86.9% | 33 / 33 | 20 / 15 | 6M | 1M |
| Q4 2025 | 83 | 8M | 51.4% | 22 / 24 | 22 / 30 | 2M | 4M |
| Q3 2025 | 92 | 10M | 67.7% | 27 / 28 | 20 / 5 | 2M | 1M |
| Q2 2025 | 70 | 9M | 61.5% | 10 / 26 | 13 / 15 | 1M | 2M |
| Q1 2025 | 75 | 10M | 65.9% | 10 / 22 | 24 / 18 | 1M | 1M |
| Q4 2024 | 84 | 9M | 64.2% | 24 / 33 | 14 / 9 | 2M | 1M |
| Q3 2024 | 71 | 9M | 58.1% | 16 / 21 | 14 / 7 | 1M | 1M |
| Q2 2024 | 63 | 8M | 57.3% | 25 / 16 | 13 / 11 | 2M | 1M |
| Q1 2024 | 49 | 7M | 47.1% | 11 / 13 | 8 / 2 | 0M | 0M |
| Q4 2023 | 40 | 7M | 44.6% | 40 / 0 | 0 / 0 | 7M | 0M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
90 funds held KRRO in Q2 2026, 67% of their shares through ETFs. Each fund counts once per quarter, from its quarter-end report.
| Fund | Shares | % of KRRO | Value | % of fund | As of |
|---|---|---|---|---|---|
| Vanguard Total Stock Market Index Fund | 311,262 | 2.11% | $4.10M | 0.00% | Jun 30, 2026 |
| iShares Russell 2000 ETF | 262,918 | 1.79% | $3.47M | 0.00% | Jun 30, 2026 |
| Vanguard Extended Market Index Fund | 135,396 | 0.92% | $1.78M | 0.00% | Jun 30, 2026 |
| Fidelity Small Cap Index Fund | 121,936 | 0.83% | $1.26M | 0.00% | Jul 31, 2026 |
| Vanguard Strategic Small-Cap Equity Fund | 106,395 | 0.72% | $1.40M | 0.04% | Jun 30, 2026 |
| iShares Russell 2000 Value ETF | 78,719 | 0.53% | $1.04M | 0.01% | Jun 30, 2026 |
| F/m Emerald Life Sciences Innovation ETF | 62,855 | 0.43% | $842.89K | 0.80% | May 31, 2026 |
| iShares Russell 2000 Growth ETF | 56,704 | 0.39% | $747.36K | 0.00% | Jun 30, 2026 |
| Fidelity Extended Market Index Fund | 35,064 | 0.24% | $470.21K | 0.00% | May 31, 2026 |
| Vanguard Russell 2000 Index Fund | 34,066 | 0.23% | $456.83K | 0.00% | May 31, 2026 |
| iShares Micro-Cap ETF | 34,046 | 0.23% | $448.73K | 0.03% | Jun 30, 2026 |
| Schwab Small-Cap Index Fund | 26,870 | 0.18% | $278.64K | 0.00% | Jul 31, 2026 |
| Vanguard Health Care Index Fund | 21,772 | 0.15% | $291.96K | 0.00% | May 31, 2026 |
| Master Small Cap Index Series | 18,948 | 0.13% | $249.73K | 0.00% | Jun 30, 2026 |
| Nuveen Small Cap Blend Index Fund | 14,880 | 0.10% | $154.31K | 0.00% | 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 |
|---|---|---|---|---|
| Ram Aiyar | President and CEO, Director | 73,659 | 0.50% | Aug 5, 2026 |
| Oliver Dolan | Senior Vice President, Finance | 16,241 | 0.11% | Sep 14, 2026 |
| Todd Chappell | Chief Operating Officer | 24,464 | 0.17% | Jul 17, 2026 |
| Jeffrey Cerio | General Counsel | 41,793 | 0.28% | Jul 17, 2026 |
| Loic A. Vincent | Chief Scientific Officer | 25,797 | 0.18% | Jul 17, 2026 |
| Olukemi Olugemo | Chief Medical Officer | – | – | Feb 5, 2025 |
| Vineet Agarwal | Chief Financial Officer | 800 | 0.01% | Feb 5, 2025 |
| Jean Francois Formela | Director | 121,219 | 0.82% | Nov 13, 2026 |
| Katharine Knobil | Director | – | – | Jun 11, 2026 |
| Timothy R. Pearson | Director | – | – | Jun 11, 2026 |
| Ali Behbahani | Director | 1,297,893 | 8.81% | Jun 11, 2026 |
| Nessan Bermingham | Director | 35,114 | 0.24% | Jun 11, 2026 |
| Rachel Meyers | Director | – | – | Jun 11, 2026 |
| Weston Nichols | 10% owner | 1,538,296 | 10.45% | Oct 26, 2026 |
| Capital Management LP Lynx1 | 10% owner | 1,624,789 | 11.03% | Oct 26, 2026 |
| NEA Partners 17, L.P. | 10% owner | 1,090,793 | 7.41% | Mar 12, 2026 |
| Nea 17 Gp, Llc | 10% owner | 1,072,936 | 7.29% | Mar 12, 2026 |
| Rick Yang | 10% owner | 1,297,893 | 8.81% | Mar 12, 2026 |
| Mohamad Makhzoumi | 10% owner | 1,297,893 | 8.81% | Mar 12, 2026 |
| Paul Edward Walker | 10% owner | 1,297,893 | 8.81% | Mar 12, 2026 |
| Edward T. Mathers | 10% owner | 1,297,893 | 8.81% | Mar 12, 2026 |
| Scott D. Sandell | 10% owner | 1,297,893 | 8.81% | Mar 12, 2026 |
| Forest Baskett | 10% owner | 1,297,893 | 8.81% | Mar 12, 2026 |
| Carmen Chang | 10% owner | 1,297,893 | 8.81% | Mar 12, 2026 |
| Anthony A. Florence Jr. | 10% owner | 1,297,893 | 8.81% | Mar 12, 2026 |
| New Enterprise Associates 17, L.P. | 10% owner | 1,297,893 | 8.81% | Mar 12, 2026 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Jean Francois Formela Director | Nov 12, 2026 | Sale(10b5-1 plan) | −6,870 | $14.30 | $98.24K | 121,219 |
| Jean Francois Formela Director | Nov 12, 2026 | Sale(10b5-1 plan) | −33,175 | $14.30 | $474.40K | 585,409 |
| Jean Francois Formela Director | Nov 11, 2026 | Sale(10b5-1 plan) | −617 | $15.60 | $9.63K | 128,089 |
| Jean Francois Formela Director | Nov 11, 2026 | Sale(10b5-1 plan) | −3,944 | $15.00 | $59.16K | 128,706 |
| Jean Francois Formela Director | Nov 11, 2026 | Sale(10b5-1 plan) | −2,984 | $15.60 | $46.55K | 618,584 |
| Jean Francois Formela Director | Nov 11, 2026 | Sale(10b5-1 plan) | −19,042 | $15.00 | $285.63K | 621,568 |
| Capital Management LP Lynx1 10% owner | Oct 26, 2026 | Buy | +25,124 | $11.75 | $295.09K | 1,624,789 |
| Capital Management LP Lynx1 10% owner | Oct 23, 2026 | Buy | +2,510 | $12.11 | $30.39K | 1,599,665 |
| Capital Management LP Lynx1 10% owner | Oct 22, 2026 | Buy | +40,000 | $11.04 | $441.46K | 1,597,155 |
| Capital Management LP Lynx1 10% owner | Oct 22, 2026 | Buy | +12,175 | $9.68 | $117.81K | 1,557,155 |
| Jean Francois Formela Director | Sep 14, 2026 | Sale(10b5-1 plan) | −6,602 | $14.12 | $93.22K | 132,650 |
| Jean Francois Formela Director | Sep 14, 2026 | Sale(10b5-1 plan) | −31,888 | $14.12 | $450.26K | 640,610 |
| Jean Francois Formela Director | Sep 11, 2026 | Sale(10b5-1 plan) | −8,450 | $13.99 | $118.22K | 672,498 |
| Jean Francois Formela Director | Sep 11, 2026 | Sale(10b5-1 plan) | −1,750 | $13.99 | $24.48K | 139,252 |
| Oliver Dolan Senior Vice President, Finance | Sep 11, 2026 | Sale(10b5-1 plan) | −5 | $13.72 | $69 | 16,241 |
| Oliver Dolan Senior Vice President, Finance | Sep 9, 2026 | Sale(10b5-1 plan) | −6 | $13.60 | $82 | 16,246 |
| Oliver Dolan Senior Vice President, Finance | Sep 8, 2026 | Sale(10b5-1 plan) | −7,347 | $13.51 | $99.26K | 16,252 |
| Jean Francois Formela Director | Aug 26, 2026 | Sale(10b5-1 plan) | −51 | $13.96 | $712 | 141,002 |
| Jean Francois Formela Director | Aug 26, 2026 | Sale(10b5-1 plan) | −249 | $13.96 | $3.48K | 680,948 |
| Jean Francois Formela Director | Aug 19, 2026 | Sale(10b5-1 plan) | −4,884 | $14.00 | $68.38K | 141,053 |
| Jean Francois Formela Director | Aug 19, 2026 | Sale(10b5-1 plan) | −23,584 | $14.00 | $330.18K | 681,197 |
| Jean Francois Formela Director | Aug 11, 2026 | Sale(10b5-1 plan) | −368 | $13.96 | $5.14K | 145,937 |
| Jean Francois Formela Director | Aug 11, 2026 | Sale(10b5-1 plan) | −1,775 | $13.96 | $24.78K | 704,781 |
| Capital Management LP Lynx1 10% owner | Aug 10, 2026 | Buy | +1,462 | $13.19 | $19.28K | 1,544,980 |
| Capital Management LP Lynx1 10% owner | Aug 6, 2026 | Buy | +5,222 | $11.40 | $59.53K | 1,543,518 |
| Ram Aiyar President and CEO, Director | Aug 4, 2026 | Sale | −5,802 | $10.84 | $62.89K | 69,046 |
| Loic A. Vincent Chief Scientific Officer | Jul 15, 2026 | Award | +7,500 | – | – | 25,797 |
| Jeffrey Cerio General Counsel | Jul 15, 2026 | Award | +6,500 | – | – | 41,793 |
| Todd Chappell Chief Operating Officer | Jul 15, 2026 | Award | +7,500 | – | – | 24,464 |
| Oliver Dolan Senior Vice President, Finance | Jul 15, 2026 | Award | +5,500 | – | – | 23,599 |
| Jean Francois Formela Director | Jul 6, 2026 | Sale(10b5-1 plan) | −8,506 | $13.96 | $118.74K | 146,305 |
| Jean Francois Formela Director | Jul 6, 2026 | Sale(10b5-1 plan) | −817 | $13.96 | $11.41K | 706,556 |
| Jean Francois Formela Director | Jul 2, 2026 | Sale(10b5-1 plan) | −14,745 | $14.03 | $206.87K | 154,811 |
| Jean Francois Formela Director | Jul 2, 2026 | Sale(10b5-1 plan) | −85,955 | $14.03 | $1.21M | 707,373 |
| Jean Francois Formela Director | Jun 24, 2026 | Sale(10b5-1 plan) | −6,979 | $14.60 | $101.89K | 169,670 |
| Jean Francois Formela Director | Jun 24, 2026 | Sale(10b5-1 plan) | −666 | $14.98 | $9.98K | 793,328 |
| Jean Francois Formela Director | Jun 24, 2026 | Sale(10b5-1 plan) | −114 | $14.98 | $1.71K | 169,556 |
| Jean Francois Formela Director | Jun 24, 2026 | Sale(10b5-1 plan) | −40,679 | $14.60 | $593.91K | 793,994 |
| Jean Francois Formela Director | Jun 23, 2026 | Sale(10b5-1 plan) | −17,426 | $14.25 | $248.32K | 176,649 |
| Jean Francois Formela Director | Jun 23, 2026 | Sale(10b5-1 plan) | −101,579 | $14.25 | $1.45M | 834,673 |
| Jean Francois Formela Director | Jun 22, 2026 | Sale(10b5-1 plan) | −580 | $13.95 | $8.09K | 194,075 |
| Jean Francois Formela Director | Jun 22, 2026 | Sale(10b5-1 plan) | −3,382 | $13.95 | $47.18K | 936,252 |
| Oliver Dolan Senior Vice President, Finance | Jun 16, 2026 | Sale | −3,383 | $10.83 | $36.64K | 18,099 |
| Loic A. Vincent Chief Scientific Officer | Jun 16, 2026 | Sale | −3,418 | $10.83 | $37.02K | 18,297 |
| Jeffrey Cerio General Counsel | Jun 16, 2026 | Sale | −6,609 | $10.83 | $71.58K | 35,293 |
| Todd Chappell Chief Operating Officer | Jun 16, 2026 | Sale | −3,168 | $10.83 | $34.31K | 16,964 |
| Ram Aiyar President and CEO, Director | May 29, 2026 | Sale | −15,152 | $12.98 | $196.67K | 74,848 |
| Jean Francois Formela Director | May 28, 2026 | Sale(10b5-1 plan) | −419 | $13.95 | $5.85K | 194,655 |
| Jean Francois Formela Director | May 28, 2026 | Sale(10b5-1 plan) | −2,441 | $13.95 | $34.05K | 939,634 |
| Ram Aiyar President and CEO, Director | May 26, 2026 | Award | +50,000 | $12.33 | $616.50K | 90,000 |
| Weston Nichols 10% owner | Mar 31, 2026 | Buy | +520 | $10.60 | $5.51K | 1,538,296 |
| Ali Behbahani Director, 10% owner | Mar 10, 2026 | Award | +207,100 | $11.11 | $2.30M | 1,297,893 |
| Mohamad Makhzoumi 10% owner | Mar 10, 2026 | Buy | +207,100 | $11.11 | $2.30M | 1,297,893 |
| Carmen Chang 10% owner | Mar 10, 2026 | Buy | +207,100 | $11.11 | $2.30M | 1,297,893 |
| Rick Yang 10% owner | Mar 10, 2026 | Buy | +207,100 | $11.11 | $2.30M | 1,297,893 |
| New Enterprise Associates 17, L.P. 10% owner | Mar 10, 2026 | Buy | +207,100 | $11.11 | $2.30M | 1,297,893 |
| Forest Baskett 10% owner | Mar 10, 2026 | Buy | +207,100 | $11.11 | $2.30M | 1,297,893 |
| Paul Edward Walker 10% owner | Mar 10, 2026 | Buy | +207,100 | $11.11 | $2.30M | 1,297,893 |
| Scott D. Sandell 10% owner | Mar 10, 2026 | Buy | +207,100 | $11.11 | $2.30M | 1,297,893 |
| Edward T. Mathers 10% owner | Mar 10, 2026 | Buy | +207,100 | $11.11 | $2.30M | 1,297,893 |
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
16.39%
2M shares short
Days to cover
8.2
At 0M shares a day
Change since last report
+0.9%
From 2M shares
Short volume, 20 days
66.7%
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 Korro Bio's stock actually held short. Settlement fails (shares not delivered on time) peaked at 10,049 shares on Sep 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 |
|---|---|---|---|---|---|
| Atlas Venture Fund XI, L.P. Shareholder | Sep 14, 2026 | 31,888 | $440.37K | Sep 14, 2026 | Private Placement |
| Atlas Venture Opportunity Fund II, L.P. Shareholder | Sep 14, 2026 | 6,602 | $91.17K | Sep 14, 2026 | Private Placement |
| Atlas Venture Fund XI, L.P. Shareholder | Sep 11, 2026 | 8,450 | $110.36K | Sep 11, 2026 | Private Placement |
| Atlas Venture Opportunity Fund II, L.P. Shareholder | Sep 11, 2026 | 1,750 | $22.86K | Sep 11, 2026 | Private Placement |
| Oliver Dolan Officer | Sep 11, 2026 | 5 | $69 | Sep 11, 2026 | Restricted Stock Vesting |
| Oliver Dolan Officer | Sep 9, 2026 | 6 | $82 | Sep 9, 2026 | Restricted Stock Vesting |
| Oliver Dolan Officer | Sep 8, 2026 | 7,347 | $99.29K | Sep 8, 2026 | Restricted Stock Vesting |
| Atlas Venture Fund XI, L.P. Shareholder | Aug 26, 2026 | 249 | $3.42K | Aug 26, 2026 | Private Placement |
| Atlas Venture Opportunity Fund II, L.P. Shareholder | Aug 26, 2026 | 51 | $700 | Aug 26, 2026 | Private Placement |
| Atlas Venture Opportunity Fund II, L.P. Shareholder | Aug 19, 2026 | 4,884 | $64.57K | Aug 19, 2026 | Private Placement |
| Atlas Venture Fund XI, L.P. Shareholder | Aug 19, 2026 | 23,584 | $311.78K | Aug 19, 2026 | Private Placement |
| Atlas Venture Opportunity Fund II, L.P. Shareholder | Aug 11, 2026 | 368 | $4.96K | Aug 11, 2026 | Private Placement |
| Atlas Venture Fund XI, L.P. Shareholder | Aug 11, 2026 | 1,775 | $23.94K | Aug 11, 2026 | Private Placement |
| Ram Aiyar Officer, Director | Aug 4, 2026 | 5,802 | $662.92K | Aug 4, 2026 | Restricted Stock Vesting |
| Atlas Venture Fund XI, L.P. Shareholder | Jul 6, 2026 | 817 | $11.44K | Jul 6, 2026 | Private Placement |
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