Korro Bio (KRRO)
Korro Bio on one page: short interest, daily short volume, fails to deliver, planned sales, large holders, 13F holders, earnings dates and insider trades. Listed on Nasdaq, classified by the SEC as pharmaceutical preparations.
1.7M
Short interest
settlement 2026-10-15
9.6
Days to cover
+3.1 days vs prior
61.2%
Short share of volume
2026-11-02
6,189
Fails to deliver
settlement 2026-10-14
Wed 11 Nov
Next earnings
estimated date
-$255K
Insider flow, 90 days
6 buys, 13 sells
As of 2026-11-02.
Short interest
FINRA, twice a month. The newest 48 settlements in the table, 48 in the chart. JSONAs of 15 October 2026, short interest in KRRO is 1,732,855 shares, up 180,871 shares over the last month. Over the last 48 readings it ranged from 244,854 shares (15 November 2024) to 1,732,855 shares (15 October 2026). The latest reading sits at the top of that range. At the reported average volume of 180K shares a day that is 9.6 days to cover.
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| Settlement | Shares short | Change | Avg daily volume | Days to cover |
|---|---|---|---|---|
| 2026-10-15 | 1,732,855 | +3.4% | 179,986 | 9.63 |
| 2026-09-30 | 1,675,219 | +7.9% | 255,628 | 6.55 |
| 2026-09-15 | 1,551,984 | +4.6% | 130,312 | 11.91 |
| 2026-08-31 | 1,483,705 | -1.9% | 71,165 | 20.85 |
| 2026-08-14 | 1,511,713 | +5.1% | 105,843 | 14.28 |
| 2026-07-31 | 1,438,506 | -1.4% | 157,016 | 9.16 |
| 2026-07-15 | 1,459,180 | -14.4% | 229,522 | 6.36 |
| 2026-06-30 | 1,705,061 | +29.2% | 367,177 | 4.64 |
| 2026-06-15 | 1,319,658 | +4.3% | 144,447 | 9.14 |
| 2026-05-29 | 1,265,439 | +5.9% | 166,458 | 7.60 |
| 2026-05-15 | 1,194,496 | +6.9% | 104,312 | 11.45 |
| 2026-04-30 | 1,117,429 | +3.0% | 71,061 | 15.72 |
| 2026-04-15 | 1,085,053 | +2.1% | 214,847 | 5.05 |
| 2026-03-31 | 1,062,337 | +4.3% | 204,575 | 5.19 |
| 2026-03-13 | 1,018,585 | -2.3% | 296,914 | 3.43 |
| 2026-02-27 | 1,042,910 | -2.2% | 142,049 | 7.34 |
| 2026-02-13 | 1,066,433 | -6.1% | 156,244 | 6.83 |
| 2026-01-30 | 1,135,240 | +4.0% | 422,528 | 2.69 |
| 2026-01-15 | 1,091,135 | -1.4% | 178,569 | 6.11 |
| 2025-12-31 | 1,106,700 | -7.7% | 184,074 | 6.01 |
| 2025-12-15 | 1,198,701 | -3.4% | 468,079 | 2.56 |
| 2025-11-28 | 1,240,508 | -13.9% | 584,274 | 2.12 |
| 2025-11-14 | 1,441,185 | +24.1% | 1,452,423 | 1.00 |
| 2025-10-31 | 1,161,662 | +9.1% | 197,567 | 5.88 |
| 2025-10-15 | 1,064,456 | -22.3% | 282,849 | 3.76 |
| 2025-09-30 | 1,369,925 | -7.3% | 237,719 | 5.76 |
| 2025-09-15 | 1,478,457 | +22.7% | 348,066 | 4.25 |
| 2025-08-29 | 1,204,826 | -2.9% | 125,996 | 9.56 |
| 2025-08-15 | 1,241,365 | +4.4% | 149,138 | 8.32 |
| 2025-07-31 | 1,189,376 | +8.0% | 129,619 | 9.18 |
| 2025-07-15 | 1,101,565 | +9.2% | 106,618 | 10.33 |
| 2025-06-30 | 1,008,963 | +9.0% | 102,976 | 9.80 |
| 2025-06-13 | 925,793 | -6.7% | 301,428 | 3.07 |
| 2025-05-30 | 992,005 | -7.3% | 92,899 | 10.68 |
| 2025-05-15 | 1,069,805 | +1.3% | 82,949 | 12.90 |
| 2025-04-30 | 1,056,492 | +6.2% | 124,748 | 8.47 |
| 2025-04-15 | 995,154 | +12.6% | 93,437 | 10.65 |
| 2025-03-31 | 884,077 | +7.0% | 136,769 | 6.46 |
| 2025-03-14 | 826,301 | -0.9% | 66,274 | 12.47 |
| 2025-02-28 | 834,167 | +2.5% | 71,182 | 11.72 |
| 2025-02-14 | 813,632 | +3.4% | 57,003 | 14.27 |
| 2025-01-31 | 786,669 | +4.7% | 62,953 | 12.50 |
| 2025-01-15 | 751,589 | +14.9% | 117,980 | 6.37 |
| 2024-12-31 | 653,905 | +50.2% | 91,428 | 7.15 |
| 2024-12-13 | 435,450 | +45.1% | 163,791 | 2.66 |
| 2024-11-29 | 300,083 | +22.6% | 82,385 | 3.64 |
| 2024-11-15 | 244,854 | -6.5% | 145,994 | 1.68 |
| 2024-10-31 | 261,960 | -4.5% | 263,977 | 1.00 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 2 November 2026, the short share of KRRO volume is 61.2%, up 11.2 points over the last five sessions. Over the last 30 readings it ranged from 40.9% (2 October 2026) to 93.5% (20 October 2026). The latest reading is 4.5 points below the 30-session average of 65.7%, on 81K shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-11-02 | 50K | 81K | 61.2% | 0 |
| 2026-10-30 | 25K | 37K | 65.6% | 0 |
| 2026-10-29 | 32K | 45K | 70.8% | 0 |
| 2026-10-28 | 50K | 109K | 46.1% | 0 |
| 2026-10-27 | 57K | 112K | 50.7% | 0 |
| 2026-10-26 | 42K | 85K | 50.0% | 0 |
| 2026-10-23 | 42K | 74K | 56.3% | 0 |
| 2026-10-22 | 99K | 184K | 53.7% | 974 |
| 2026-10-21 | 37K | 49K | 76.5% | 0 |
| 2026-10-20 | 129K | 138K | 93.5% | 0 |
| 2026-10-19 | 43K | 53K | 81.2% | 0 |
| 2026-10-16 | 26K | 42K | 62.6% | 0 |
| 2026-10-15 | 169K | 187K | 90.8% | 0 |
| 2026-10-14 | 68K | 80K | 85.3% | 0 |
| 2026-10-13 | 70K | 101K | 69.2% | 0 |
| 2026-10-12 | 21K | 37K | 56.4% | 0 |
| 2026-10-09 | 20K | 41K | 48.5% | 0 |
| 2026-10-08 | 23K | 31K | 74.3% | 0 |
| 2026-10-07 | 28K | 46K | 61.4% | 0 |
| 2026-10-06 | 29K | 52K | 55.0% | 0 |
| 2026-10-05 | 25K | 40K | 63.4% | 0 |
| 2026-10-02 | 24K | 58K | 40.9% | 0 |
| 2026-10-01 | 22K | 30K | 73.1% | 0 |
| 2026-09-30 | 27K | 40K | 68.5% | 0 |
| 2026-09-29 | 23K | 29K | 80.5% | 3 |
| 2026-09-28 | 24K | 40K | 59.5% | 0 |
| 2026-09-25 | 22K | 37K | 60.9% | 0 |
| 2026-09-24 | 48K | 69K | 70.0% | 0 |
| 2026-09-23 | 48K | 62K | 77.2% | 0 |
| 2026-09-22 | 38K | 57K | 67.4% | 0 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 14 October 2026, the fails-to-deliver balance in KRRO is 6,189 shares, up 3,808 shares over the last settlement date. Over the last 30 readings it ranged from 3 shares (14 August 2026) to 18,769 shares (22 July 2026).
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-10-14 | 6,189 | $8.81 | $55K |
| 2026-10-13 | 2,381 | $9.37 | $22K |
| 2026-10-07 | 2,469 | $9.76 | $24K |
| 2026-10-06 | 1,336 | $9.97 | $13K |
| 2026-10-01 | 7,025 | $9.91 | $70K |
| 2026-09-29 | 1,110 | $9.51 | $11K |
| 2026-09-28 | 10,049 | $9.57 | $96K |
| 2026-09-24 | 1,147 | $9.83 | $11K |
| 2026-09-23 | 192 | $10.34 | $2K |
| 2026-09-21 | 8,318 | $10.02 | $83K |
| 2026-09-18 | 4,717 | $11.80 | $56K |
| 2026-09-16 | 5,792 | $14.07 | $81K |
| 2026-09-14 | 911 | $13.81 | $13K |
| 2026-09-11 | 5,970 | $13.06 | $78K |
| 2026-09-04 | 11 | $11.62 | $128 |
| 2026-08-27 | 147 | $13.68 | $2K |
| 2026-08-20 | 237 | $13.95 | $3K |
| 2026-08-19 | 12 | $13.22 | $159 |
| 2026-08-14 | 3 | $13.29 | $40 |
| 2026-08-10 | 6,027 | $13.25 | $80K |
| 2026-08-05 | 118 | $11.35 | $1K |
| 2026-08-03 | 4,695 | $10.37 | $49K |
| 2026-07-31 | 3,190 | $10.45 | $33K |
| 2026-07-30 | 4,681 | $10.07 | $47K |
| 2026-07-28 | 15,172 | $10.72 | $163K |
| 2026-07-24 | 55 | $11.53 | $634 |
| 2026-07-22 | 18,769 | $11.96 | $224K |
| 2026-07-17 | 8,182 | $12.28 | $100K |
| 2026-07-16 | 7,624 | $13.03 | $99K |
| 2026-07-15 | 1,525 | $13.27 | $20K |
Insider trades
SEC Form 4, newest first. JSONOver the last 90 days KRRO insiders reported 6 open-market buys ($964K) against 13 sells ($1.2M), so the dollar flow leans toward selling. Latest filing: Lynx1 Capital Management LP (10% owner) on 2026-10-26.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-10-26 | Lynx1 Capital Management LP | 10% owner | Buy | 25K | $11.75 | $295K | 1.6M |
| 2026-10-23 | Lynx1 Capital Management LP | 10% owner | Buy | 3K | $12.11 | $30K | 1.6M |
| 2026-10-22 | Lynx1 Capital Management LP | 10% owner | Buy | 40K | $11.04 | $441K | 1.6M |
| 2026-10-22 | Lynx1 Capital Management LP | 10% owner | Buy | 12K | $9.68 | $118K | 1.6M |
| 2026-09-14 | FORMELA JEAN FRANCOIS | Director | Sell | 7K | $14.12 | $93K | 133K |
| 2026-09-14 | FORMELA JEAN FRANCOIS | Director | Sell | 32K | $14.12 | $450K | 641K |
| 2026-09-11 | FORMELA JEAN FRANCOIS | Director | Sell | 2K | $13.99 | $24K | 139K |
| 2026-09-11 | FORMELA JEAN FRANCOIS | Director | Sell | 8K | $13.99 | $118K | 672K |
| 2026-09-11 | Dolan Oliver | Senior Vice President, Finance | Sell | 5 | $13.72 | $69 | 16K |
| 2026-09-09 | Dolan Oliver | Senior Vice President, Finance | Sell | 6 | $13.60 | $82 | 16K |
| 2026-09-08 | Dolan Oliver | Senior Vice President, Finance | Sell | 7K | $13.51 | $99K | 16K |
| 2026-08-26 | FORMELA JEAN FRANCOIS | Director | Sell | 51 | $13.96 | $712 | 141K |
| 2026-08-26 | FORMELA JEAN FRANCOIS | Director | Sell | 249 | $13.96 | $3K | 681K |
| 2026-08-19 | FORMELA JEAN FRANCOIS | Director | Sell | 5K | $14.00 | $68K | 141K |
| 2026-08-19 | FORMELA JEAN FRANCOIS | Director | Sell | 24K | $14.00 | $330K | 681K |
| 2026-08-11 | FORMELA JEAN FRANCOIS | Director | Sell | 368 | $13.96 | $5K | 146K |
| 2026-08-11 | FORMELA JEAN FRANCOIS | Director | Sell | 2K | $13.96 | $25K | 705K |
| 2026-08-10 | Lynx1 Capital Management LP | 10% owner | Buy | 1K | $13.19 | $19K | 1.5M |
| 2026-08-06 | Lynx1 Capital Management LP | 10% owner | Buy | 5K | $11.40 | $60K | 1.5M |
| 2026-08-04 | Aiyar Ram | President and CEO | Sell | 6K | $10.84 | $63K | 69K |
| 2026-07-15 | Vincent Loic A | Chief Scientific Officer | Grant | 8K | $0.00 | $0 | 26K |
| 2026-07-15 | Dolan Oliver | Senior Vice President, Finance | Grant | 6K | $0.00 | $0 | 24K |
| 2026-07-15 | Chappell Todd | Chief Operating Officer | Grant | 8K | $0.00 | $0 | 24K |
| 2026-07-15 | Cerio Jeffrey | General Counsel | Grant | 7K | $0.00 | $0 | 42K |
| 2026-07-06 | FORMELA JEAN FRANCOIS | Director | Sell | 9K | $13.96 | $119K | 146K |
| 2026-07-06 | FORMELA JEAN FRANCOIS | Director | Sell | 817 | $13.96 | $11K | 707K |
| 2026-07-02 | FORMELA JEAN FRANCOIS | Director | Sell | 15K | $14.03 | $207K | 155K |
| 2026-07-02 | FORMELA JEAN FRANCOIS | Director | Sell | 86K | $14.03 | $1.2M | 707K |
| 2026-06-24 | FORMELA JEAN FRANCOIS | Director | Sell | 7K | $14.60 | $102K | 170K |
| 2026-06-24 | FORMELA JEAN FRANCOIS | Director | Sell | 666 | $14.98 | $10K | 793K |
| 2026-06-24 | FORMELA JEAN FRANCOIS | Director | Sell | 114 | $14.98 | $2K | 170K |
| 2026-06-24 | FORMELA JEAN FRANCOIS | Director | Sell | 41K | $14.60 | $594K | 794K |
| 2026-06-23 | FORMELA JEAN FRANCOIS | Director | Sell | 17K | $14.25 | $248K | 177K |
| 2026-06-23 | FORMELA JEAN FRANCOIS | Director | Sell | 102K | $14.25 | $1.4M | 835K |
| 2026-06-22 | FORMELA JEAN FRANCOIS | Director | Sell | 580 | $13.95 | $8K | 194K |
| 2026-06-22 | FORMELA JEAN FRANCOIS | Director | Sell | 3K | $13.95 | $47K | 936K |
| 2026-06-16 | Dolan Oliver | Senior Vice President, Finance | Sell | 3K | $10.83 | $37K | 18K |
| 2026-06-16 | Cerio Jeffrey | General Counsel | Sell | 7K | $10.83 | $72K | 35K |
| 2026-06-16 | Vincent Loic A | Chief Scientific Officer | Sell | 3K | $10.83 | $37K | 18K |
| 2026-06-16 | Chappell Todd | Chief Operating Officer | Sell | 3K | $10.83 | $34K | 17K |
| 2026-05-29 | Aiyar Ram | President and CEO | Sell | 15K | $12.98 | $197K | 75K |
| 2026-05-28 | FORMELA JEAN FRANCOIS | Director | Sell | 419 | $13.95 | $6K | 195K |
| 2026-05-28 | FORMELA JEAN FRANCOIS | Director | Sell | 2K | $13.95 | $34K | 940K |
| 2026-05-26 | Aiyar Ram | President and CEO | Grant | 50K | $12.33 | $617K | 90K |
| 2026-03-31 | Nichols Weston | TenPercentOwner | Buy | 520 | $10.60 | $6K | 1.5M |
| 2026-03-31 | Lynx1 Capital Management LP | 10% owner | Buy | 520 | $10.60 | $6K | 1.5M |
| 2026-03-10 | Yang Rick | 10% owner | Buy | 207K | $11.11 | $2.3M | 1.3M |
| 2026-03-10 | SANDELL SCOTT D | 10% owner | Buy | 207K | $11.11 | $2.3M | 1.3M |
| 2026-03-10 | New Enterprise Associates 17, L.P. | 10% owner | Buy | 207K | $11.11 | $2.3M | 1.3M |
| 2026-03-10 | Mathers Edward T | 10% owner | Buy | 207K | $11.11 | $2.3M | 1.3M |
| 2026-03-10 | Walker Paul Edward | 10% owner | Buy | 207K | $11.11 | $2.3M | 1.3M |
| 2026-03-10 | Makhzoumi Mohamad | 10% owner | Buy | 207K | $11.11 | $2.3M | 1.3M |
| 2026-03-10 | Florence Anthony A. Jr. | 10% owner | Buy | 207K | $11.11 | $2.3M | 1.3M |
| 2026-03-10 | Chang Carmen | 10% owner | Buy | 207K | $11.11 | $2.3M | 1.3M |
| 2026-03-10 | Behbahani Ali | Director, 10% owner | Grant | 207K | $11.11 | $2.3M | 1.3M |
| 2026-03-10 | BASKETT FOREST | 10% owner | Buy | 207K | $11.11 | $2.3M | 1.3M |
| 2026-02-02 | Aiyar Ram | President and CEO | Grant | 40K | $0.00 | $0 | 40K |
| 2025-12-15 | Vincent Loic A | Chief Scientific Officer | Grant | 22K | $0.00 | $0 | 22K |
| 2025-12-15 | Dolan Oliver | Senior Vice President, Finance | Grant | 21K | $0.00 | $0 | 21K |
| 2025-12-15 | Chappell Todd | Chief Operating Officer | Grant | 20K | $0.00 | $0 | 20K |
| 2025-12-15 | Cerio Jeffrey | General Counsel | Grant | 42K | $0.00 | $0 | 42K |
| 2024-11-11 | Agarwal Vineet | Chief Financial Officer | Exercise or conversion | 800 | $11.68 | $9K | 800 |
| 2024-11-11 | Agarwal Vineet | Chief Financial Officer | Sell | 800 | $70.00 | $56K | 0 |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 115 | $74.56 | $9K | 8K |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 23 | $77.00 | $2K | 8K |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Exercise or conversion | 9K | $11.68 | $108K | 9K |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Exercise or conversion | 953 | $14.98 | $14K | 10K |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 2K | $71.51 | $145K | 8K |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 164 | $73.71 | $12K | 8K |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 260 | $77.55 | $20K | 8K |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 25 | $82.89 | $2K | 0 |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 317 | $81.48 | $26K | 25 |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 5K | $80.50 | $399K | 342 |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 2K | $79.79 | $145K | 5K |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 457 | $78.59 | $36K | 7K |
| 2024-10-17 | Agarwal Vineet | Chief Financial Officer | Sell | 56 | $76.00 | $4K | 8K |
| 2024-04-22 | Atlas Venture Associates Opportunity II, LP | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 195K |
| 2024-04-22 | FORMELA JEAN FRANCOIS | Director | Grant | 18K | $56.00 | $1000K | 195K |
| 2024-04-22 | Yang Rick | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 1.1M |
| 2024-04-22 | SANDELL SCOTT D | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 1.1M |
| 2024-04-22 | Mathers Edward T | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 1.1M |
| 2024-04-22 | Makhzoumi Mohamad | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 1.1M |
| 2024-04-22 | Florence Anthony A. Jr. | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 1.1M |
| 2024-04-22 | Walker Paul Edward | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 1.1M |
| 2024-04-22 | Behbahani Ali | Director,TenPercentOwner | Grant | 18K | $56.00 | $1000K | 1.1M |
| 2024-04-22 | BASKETT FOREST | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 1.1M |
| 2024-04-22 | NEA Partners 17, L.P. | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 1.1M |
| 2024-04-22 | Chang Carmen | TenPercentOwner | Buy | 18K | $56.00 | $1000K | 1.1M |
| 2023-11-22 | Lucchino David L. | Director | Sell | 202 | $38.82 | $8K | 22K |
| 2023-11-22 | Lucchino David L. | Director | Sell | 230 | $36.74 | $8K | 23K |
| 2023-11-22 | Lucchino David L. | Director | Sell | 110 | $35.99 | $4K | 23K |
| 2023-11-22 | Lucchino David L. | Director | Sell | 614 | $37.98 | $23K | 22K |
| 2023-11-10 | Lucchino David L. | Director | Sell | 34 | $46.23 | $2K | 23K |
| 2023-11-10 | Lucchino David L. | Director | Sell | 67 | $45.53 | $3K | 23K |
| 2023-11-10 | Lucchino David L. | Director | Sell | 225 | $43.17 | $10K | 24K |
| 2023-11-10 | Lucchino David L. | Director | Sell | 191 | $44.01 | $8K | 23K |
| 2023-11-10 | Lucchino David L. | Director | Sell | 41 | $41.94 | $2K | 24K |
| 2023-11-10 | Lucchino David L. | Director | Sell | 373 | $39.59 | $15K | 24K |
| 2023-11-10 | Lucchino David L. | Director | Sell | 37 | $37.92 | $1K | 24K |
| 2023-11-03 | FORMELA JEAN FRANCOIS | Director | Grant | 942K | price not stated in the filing | not stated | 942K |
Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are rarer.
Planned sales (Form 144)
Newest first. JSON9 Form 144 notices on file for KRRO worth $1.1M at the prices reported; 3 in the last 90 days worth $99K. Latest: Dolan Oliver filed on 2026-09-11 to sell 5 shares ($69) from 2026-09-11.
| Filed | Seller | Shares | Market value | Of outstanding | Sale from | Broker |
|---|---|---|---|---|---|---|
| 2026-09-11 | Dolan OliverOfficer | 5 | $69 | 0.000% | 2026-09-11 | Fidelity Brokerage Services LLC |
| 2026-09-09 | Dolan OliverOfficer | 6 | $82 | 0.000% | 2026-09-09 | Fidelity Brokerage Services LLC |
| 2026-09-08 | Dolan OliverOfficer | 7K | $99K | 0.050% | 2026-09-08 | Fidelity Brokerage Services LLC |
| 2026-08-04 | Aiyar RamOfficer, Director | 6K | $663K | 0.040% | 2026-08-04 | Fidelity Brokerage Services LLC |
| 2026-06-16 | Vincent Loic AOfficer | 3K | $37K | 0.024% | 2026-06-16 | Fidelity Brokerage Services LLC |
| 2026-06-16 | Dolan OliverOfficer | 3K | $37K | 0.023% | 2026-06-16 | Fidelity Brokerage Services LLC |
| 2026-06-16 | Chappell ToddOfficer | 3K | $34K | 0.022% | 2026-06-16 | Fidelity Brokerage Services LLC |
| 2026-06-16 | Cerio JeffreyOfficer | 7K | $72K | 0.046% | 2026-06-16 | Fidelity Brokerage Services LLC |
| 2026-05-29 | Aiyar RamOfficer | 15K | $197K | 0.105% | 2026-05-29 | Fidelity Brokerage Services LLC |
Large holders (13D and 13G)
One row per reporting person with its latest filing, newest first. JSON29 holders report 5% or more of KRRO in their latest filing, 12 on Schedule 13D (active intent). The largest reported stake is Lynx1 Capital Management LP at 10.7% of the class (1,538,296 shares), filed 2026-04-02 for an event on 2026-03-31.
| Filed | Form | Holder | Shares | Of class | Event |
|---|---|---|---|---|---|
| 2026-10-27 | 13G/Ano. 1 | BlackRock, Inc.parent holding company | 718K | 4.9% | 2026-09-30 |
| 2026-08-14 | 13G/Ano. 1 | BALYASNY ASSET MANAGEMENT L.P.investment adviser, partnership | 952K | 6.6% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | BAM GP LLCparent holding company, other entity | 952K | 6.6% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Balyasny Asset Management Holdings LPparent holding company, partnership | 952K | 6.6% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Dames GP LLCparent holding company, other entity | 952K | 6.6% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Dmitry Balyasnyparent holding company, individual | 952K | 6.6% | 2026-06-30 |
| 2026-08-04 | 13D/Ano. 1 | Atlas Venture Fund XI, L.P.partnership | 707K | 4.9% | 2026-06-24 |
| 2026-08-04 | 13D/Ano. 1 | Atlas Venture Associates XI, L.P.partnership | 707K | 4.9% | 2026-06-24 |
| 2026-08-04 | 13D/Ano. 1 | Atlas Venture Associates XI, LLCother entity | 707K | 4.9% | 2026-06-24 |
| 2026-08-04 | 13D/Ano. 1 | Atlas Venture Opportunity Fund II, L.P.partnership | 146K | 1.0% | 2026-06-24 |
| 2026-08-04 | 13D/Ano. 1 | Atlas Venture Associates Opportunity II, L.P.partnership | 146K | 1.0% | 2026-06-24 |
| 2026-08-04 | 13D/Ano. 1 | Atlas Venture Associates Opportunity II, LLCother entity | 146K | 1.0% | 2026-06-24 |
| 2026-05-15 | 13G/Ano. 1 | Steven A. Cohenindividual | 277K | 1.9% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 1 | 72 Investment Holdings, LLCother entity | 277K | 1.9% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 1 | Differentiated Ventures Investments, LLCother entity | 277K | 1.9% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 1 | Point72 Biotech Private Investments, LLCother entity | 277K | 1.9% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 1 | Point72 Capital Advisors, Inc.corporation | 0 | 0.0% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 1 | Point72 Asset Management, L.P.partnership | 0 | 0.0% | 2026-03-31 |
| 2026-04-02 | 13G/Ano. 1 | Lynx1 Capital Management LPpartnership | 1.5M | 10.7% | 2026-03-31 |
| 2026-04-02 | 13G/Ano. 1 | Weston Nicholsindividual | 1.5M | 10.7% | 2026-03-31 |
| 2026-03-27 | 13G/Ano. 1 | The Vanguard Groupinvestment adviser | 0 | 0.0% | 2026-03-13 |
| 2026-03-17 | 13G | Venrock Healthcare Capital Partners III, L.P.partnership | 1.5M | 9.9% | 2026-03-10 |
| 2026-03-17 | 13G | VHCP Co-Investment Holdings III, LLCother entity | 1.5M | 9.9% | 2026-03-10 |
| 2026-03-17 | 13G | Venrock Healthcare Capital Partners EG, L.P.partnership | 1.5M | 9.9% | 2026-03-10 |
| 2026-03-17 | 13G | VHCP Management III, LLCother entity | 1.5M | 9.9% | 2026-03-10 |
| 2026-03-17 | 13G | VHCP Management EG, LLCother entity | 1.5M | 9.9% | 2026-03-10 |
| 2026-03-17 | 13G | Nimish Shahindividual | 1.5M | 9.9% | 2026-03-10 |
| 2026-03-17 | 13G | Bong Y. Kohindividual | 1.5M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | New Enterprise Associates 17, L.P.partnership | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | NEA Partners 17, L.P.partnership | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | NEA 17 GP, LLCother entity | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | Forest Baskettindividual | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | Ali Behbahaniindividual | 1.5M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | Carmen Changindividual | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | Anthony A. Florence, Jr.individual | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | Mohamad H. Makhzoumiindividual | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | Edward T. Mathersindividual | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | Scott D. Sandellindividual | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | Paul Walkerindividual | 1.4M | 9.9% | 2026-03-10 |
| 2026-03-12 | 13D/Ano. 2 | Rick Yangindividual | 1.4M | 9.9% | 2026-03-10 |
| 2026-02-17 | 13G/Ano. 2 | DRIEHAUS CAPITAL MANAGEMENT LLCinvestment adviser | 0 | 0.0% | 2025-12-31 |
| 2026-02-13 | 13G | Nantahala Capital Management, LLCinvestment adviser | 600K | 6.4% | 2025-12-31 |
| 2026-02-13 | 13G | Wilmot B. Harkeyparent holding company | 600K | 6.4% | 2025-12-31 |
| 2026-02-13 | 13G | Daniel Mackparent holding company | 600K | 6.4% | 2025-12-31 |
| 2026-02-05 | 13G/Ano. 2 | FMR LLCparent holding company | 38K | 0.4% | 2025-12-31 |
| 2026-02-05 | 13G/Ano. 2 | Abigail P. Johnsonindividual | 38K | 0.4% | 2025-12-31 |
13F holders
Tracked managers holding KRRO at their latest 13F. JSON6 of the 30 tracked managers held KRRO at their latest 13F, $10.3M in total at quarter-end prices. AQR Capital Management is the largest at $3.9M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 5 added shares and 1 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| AQR Capital Management | 2026-06-30 | 299K | $3.9M | 0.00% | +31K |
| Two Sigma Investments | 2026-06-30 | 178K | $2.3M | 0.00% | +13K |
| Millennium Management | 2026-06-30 | 118K | $1.6M | 0.00% | +55K |
| Renaissance Technologies | 2026-06-30 | 111K | $1.5M | 0.00% | -26K |
| Citadel Advisors | 2026-06-30 | 40K | $532K | 0.00% | +9K |
| D. E. Shaw & Co. | 2026-06-30 | 34K | $451K | 0.00% | new |
Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.
What this page is
Korro Bio in the regulatory record
Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page puts those series for one ticker on one URL, with planned sales, large holders, 13F holders and financials beside them, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.
Each section has its own history table, a one-line summary of the latest figures and its own JSON and CSV links, and says when its source last updated.
This page follows Korro Bio (KRRO), SEC CIK 1703647, listed on Nasdaq, classified by the SEC as pharmaceutical preparations. The cross-market tables live on the short interest and insider transactions hubs.
Source and updates
- Short interest
- FINRA consolidated short interestSource: FINRA.Twice a month, about eight business days after settlement. Latest 2026-10-15.JSON and CSV
- Daily short volume
- FINRA Reg SHO daily filesSource: FINRA.Every trading day, the morning after FINRA posts it. Latest 2026-11-02.JSON and CSV
- Fails to deliver
- SEC fails-to-deliver dataSource: SEC.Twice a month, a few weeks after the half month ends. Latest 2026-10-14.JSON and CSV
- Planned sales
- SEC EDGAR Form 144Source: SEC.New notices appear shortly after the SEC posts them; a notice is filed on or before the sale. Latest 2026-09-11.JSON and CSV
- Large holders
- SEC EDGAR Schedule 13D and 13GSource: SEC.New filings appear shortly after the SEC posts them. A 13D is due within five business days of crossing 5%; a 13G follows the passive schedule. Latest 2026-10-27.JSON and CSV
- 13F holders
- SEC EDGAR Form 13F-HRSource: SEC.Quarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
- Earnings dates
- SEC EDGAR 8-K filings (Item 2.02)Source: SEC.Twice a day. Reported dates come from the company's 8-K filings; the next date is marked as an estimate until the 8-K arrives. Latest 2026-08-06.JSON and CSV
- Insider trades
- SEC EDGAR Form 4Source: SEC.New filings appear shortly after the SEC posts them; they're due two business days after the trade. Latest 2026-10-26.JSON and CSV
- Company record
- EDGAR filing index for CIK 1703647Ticker, name and exchange from the SEC's company list, refreshed weekly.
- Rate limits
- 10 requests a minute without a key, 30 with a free key from a free account.
How to read it
- Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
- Insider buys next to a large short position are rare and stand out; insider sells next to one are common and mean little.
- Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.
Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.
Other companies the SEC classifies as pharmaceutical preparations
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- SWSmurfit Westrock
- SWKStanley Black & Decker
- SWKSSkyworks Solutions
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- SYFSynchrony Financial
- SYKStryker
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Datasets
Frequently Asked Questions
How much of KRRO is sold short?
1,732,855 shares were held short at the 2026-10-15 settlement, 9.6 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.
What is KRRO's daily short volume?
On 2026-11-02, 49,732 of the 81,325 KRRO shares reported to FINRA were sold short, 61.2% of the day's reported volume. Short volume is a flow for one day, not a position.
Does KRRO have fails to deliver?
The SEC's latest file shows 6,189 KRRO shares failed to deliver at settlement 2026-10-14. Fails are reported per settlement date and published twice a month with a lag.
Are KRRO insiders buying or selling?
Over the last 90 days KRRO insiders reported 6 open-market buys ($964K) against 13 sells ($1.2M), so the dollar flow leans toward selling. Latest filing: Lynx1 Capital Management LP (10% owner) on 2026-10-26.
Have KRRO insiders filed to sell?
9 Form 144 notices on file for KRRO worth $1.1M at the prices reported; 3 in the last 90 days worth $99K. Latest: Dolan Oliver filed on 2026-09-11 to sell 5 shares ($69) from 2026-09-11.
Who owns 5% or more of KRRO?
29 holders report 5% or more of KRRO in their latest filing, 12 on Schedule 13D (active intent). The largest reported stake is Lynx1 Capital Management LP at 10.7% of the class (1,538,296 shares), filed 2026-04-02 for an event on 2026-03-31.
Which tracked 13F managers own KRRO?
6 of the 30 tracked 13F managers held KRRO shares at their latest filing, $10.3M in all. The largest: Cliff Asness's AQR Capital Management (299K shares, $3.9M), Two Sigma Investments (178K shares, $2.3M), Izzy Englander's Millennium Management (118K shares, $1.6M), Renaissance Technologies (111K shares, $1.5M), Ken Griffin's Citadel Advisors (40K shares, $532K), D. E. Shaw & Co. (34K shares, $451K).
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.