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Korro Bio, Inc.

KRRO
Exchange
Nasdaq
Industry
Pharmaceutical Preparations
SEC CIK
0001703647

In the last 90 days, Korro Bio, Inc. insiders filed 1 open-market purchase and 6 sales; 106 institutions reported holding it in 13F filings for Q2 2026, worth $190.1M in total; no superinvestor holds it.

Four kinds of short-selling data, each measuring something different:

  • Short interest: shares sold short and not yet bought back, as of a settlement date. FINRA publishes it twice a month, about eight business days after the settlement date.
  • Daily short volume: shares sold short each day in off-exchange trades reported to FINRA. It counts trades, not open positions, and is published the next day.
  • Fails-to-deliver: shares not delivered by the settlement date. The SEC publishes them twice a month, about two weeks late.
  • ATS (dark pool) volume: weekly volume on alternative trading systems and other off-exchange venues. FINRA publishes it two to four weeks after the week.

More in the glossary.

Short interest

Shares sold short and not yet bought back, from FINRA, on every settlement date in the last two years.

Short interest
1.75M
Shares, settlement Oct 30, 2026
Change
+16.3K
+0.9% vs. Oct 15, 2026
Days to cover
8.18
Short interest ÷ average daily volume
Average daily volume
213.9K
Shares, as reported by FINRA
Short interest by settlement date
Oct 31, 2024: 261,960 sharesNov 15, 2024: 244,854 sharesNov 29, 2024: 300,083 sharesDec 13, 2024: 435,450 sharesDec 31, 2024: 653,905 sharesJan 15, 2025: 751,589 sharesJan 31, 2025: 786,669 sharesFeb 14, 2025: 813,632 sharesFeb 28, 2025: 834,167 sharesMar 14, 2025: 826,301 sharesMar 31, 2025: 884,077 sharesApr 15, 2025: 995,154 sharesApr 30, 2025: 1,056,492 sharesMay 15, 2025: 1,069,805 sharesMay 30, 2025: 992,005 sharesJun 13, 2025: 925,793 sharesJun 30, 2025: 1,008,963 sharesJul 15, 2025: 1,101,565 sharesJul 31, 2025: 1,189,376 sharesAug 15, 2025: 1,241,365 sharesAug 29, 2025: 1,204,826 sharesSep 15, 2025: 1,478,457 sharesSep 30, 2025: 1,369,925 sharesOct 15, 2025: 1,064,456 sharesOct 31, 2025: 1,161,662 sharesNov 14, 2025: 1,441,185 sharesNov 28, 2025: 1,240,508 sharesDec 15, 2025: 1,198,701 sharesDec 31, 2025: 1,106,700 sharesJan 15, 2026: 1,091,135 sharesJan 30, 2026: 1,135,240 sharesFeb 13, 2026: 1,066,433 sharesFeb 27, 2026: 1,042,910 sharesMar 13, 2026: 1,018,585 sharesMar 31, 2026: 1,062,337 sharesApr 15, 2026: 1,085,053 sharesApr 30, 2026: 1,117,429 sharesMay 15, 2026: 1,194,496 sharesMay 29, 2026: 1,265,439 sharesJun 15, 2026: 1,319,658 sharesJun 30, 2026: 1,705,061 sharesJul 15, 2026: 1,459,180 sharesJul 31, 2026: 1,438,506 sharesAug 14, 2026: 1,511,713 sharesAug 31, 2026: 1,483,705 sharesSep 15, 2026: 1,551,984 sharesSep 30, 2026: 1,675,219 sharesOct 15, 2026: 1,732,855 sharesOct 30, 2026: 1,749,169 shares
Short interest in KRRO by settlement date
Settlement dateShort interestChangeChange %Avg. daily volumeDays to cover
Oct 30, 20261.75M+16.3K+0.9%213.9K8.18
Oct 15, 20261.73M+57.6K+3.4%180.0K9.63
Sep 30, 20261.68M+123.2K+7.9%255.6K6.55
Sep 15, 20261.55M+68.3K+4.6%130.3K11.91
Aug 31, 20261.48M−28.0K−1.9%71.2K20.85
Aug 14, 20261.51M+73.2K+5.1%105.8K14.28
Jul 31, 20261.44M−20.7K−1.4%157.0K9.16
Jul 15, 20261.46M−245.9K−14.4%229.5K6.36
Jun 30, 20261.71M+385.4K+29.2%367.2K4.64
Jun 15, 20261.32M+54.2K+4.3%144.4K9.14
May 29, 20261.27M+70.9K+5.9%166.5K7.60
May 15, 20261.19M+77.1K+6.9%104.3K11.45
Apr 30, 20261.12M+32.4K+3.0%71.1K15.72
Apr 15, 20261.09M+22.7K+2.1%214.8K5.05
Mar 31, 20261.06M+43.8K+4.3%204.6K5.19
Mar 13, 20261.02M−24.3K−2.3%296.9K3.43
Feb 27, 20261.04M−23.5K−2.2%142.0K7.34
Feb 13, 20261.07M−68.8K−6.1%156.2K6.83
Jan 30, 20261.14M+44.1K+4.0%422.5K2.69
Jan 15, 20261.09M−15.6K−1.4%178.6K6.11
Dec 31, 20251.11M−92.0K−7.7%184.1K6.01
Dec 15, 20251.20M−41.8K−3.4%468.1K2.56
Nov 28, 20251.24M−200.7K−13.9%584.3K2.12
Nov 14, 20251.44M+279.5K+24.1%1.45M1.00
Oct 31, 20251.16M+97.2K+9.1%197.6K5.88
Oct 15, 20251.06M−305.5K−22.3%282.8K3.76
Sep 30, 20251.37M−108.5K−7.3%237.7K5.76
Sep 15, 20251.48M+273.6K+22.7%348.1K4.25
Aug 29, 20251.20M−36.5K−2.9%126.0K9.56
Aug 15, 20251.24M+52.0K+4.4%149.1K8.32
Jul 31, 20251.19M+87.8K+8.0%129.6K9.18
Jul 15, 20251.10M+92.6K+9.2%106.6K10.33
Jun 30, 20251.01M+83.2K+9.0%103.0K9.80
Jun 13, 2025925.8K−66.2K−6.7%301.4K3.07
May 30, 2025992.0K−77.8K−7.3%92.9K10.68
May 15, 20251.07M+13.3K+1.3%82.9K12.90
Apr 30, 20251.06M+61.3K+6.2%124.7K8.47
Apr 15, 2025995.2K+111.1K+12.6%93.4K10.65
Mar 31, 2025884.1K+57.8K+7.0%136.8K6.46
Mar 14, 2025826.3K−7.87K−0.9%66.3K12.47
Feb 28, 2025834.2K+20.5K+2.5%71.2K11.72
Feb 14, 2025813.6K+27.0K+3.4%57.0K14.27
Jan 31, 2025786.7K+35.1K+4.7%63.0K12.50
Jan 15, 2025751.6K+97.7K+14.9%118.0K6.37
Dec 31, 2024653.9K+218.5K+50.2%91.4K7.15
Dec 13, 2024435.4K+135.4K+45.1%163.8K2.66
Nov 29, 2024300.1K+55.2K+22.6%82.4K3.64
Nov 15, 2024244.9K−17.1K−6.5%146.0K1.68
Oct 31, 2024262.0K−12.3K−4.5%264.0K1.00

Fails-to-deliver

Shares that weren't delivered by the settlement date, from the SEC, for the last 30 dates with fails. The price is the previous day's closing price published by the SEC.

Fails-to-deliver in KRRO by settlement date
Settlement dateSharesPriceValue
Oct 14, 20266,189$8.81$54.5K
Oct 13, 20262,381$9.37$22.3K
Oct 7, 20262,469$9.76$24.1K
Oct 6, 20261,336$9.97$13.3K
Oct 1, 20267,025$9.91$69.6K
Sep 29, 20261,110$9.51$10.6K
Sep 28, 202610,049$9.57$96.2K
Sep 24, 20261,147$9.83$11.3K
Sep 23, 2026192$10.34$1.99K
Sep 21, 20268,318$10.02$83.3K
Sep 18, 20264,717$11.80$55.7K
Sep 16, 20265,792$14.07$81.5K
Sep 14, 2026911$13.81$12.6K
Sep 11, 20265,970$13.06$78.0K
Sep 4, 202611$11.62$127.82
Aug 27, 2026147$13.68$2.01K
Aug 20, 2026237$13.95$3.31K
Aug 19, 202612$13.22$158.64
Aug 14, 20263$13.29$39.87
Aug 10, 20266,027$13.25$79.9K
Aug 5, 2026118$11.35$1.34K
Aug 3, 20264,695$10.37$48.7K
Jul 31, 20263,190$10.45$33.3K
Jul 30, 20264,681$10.07$47.1K
Jul 28, 202615,172$10.72$162.6K
Jul 24, 202655$11.53$634.15
Jul 22, 202618,769$11.96$224.5K
Jul 17, 20268,182$12.28$100.5K
Jul 16, 20267,624$13.03$99.3K
Jul 15, 20261,525$13.27$20.2K

Daily short volume

Off-exchange short-sale volume, not short interest: shares sold short each day in trades reported to FINRA, for the last 30 trading days.

The short volume ratio isn't a sentiment gauge: market makers sell short to fill buy orders and to hedge, so short sales are usually about half of off-exchange volume.

Off-exchange short volume in KRRO by trade date
Trade dateShort volumeShort exemptOff-exchange volumeShort volume ratio
Nov 13, 202618,907027,03969.9%
Nov 12, 202673,9625,92682,96389.2%
Nov 11, 202652,7867,75165,80380.2%
Nov 10, 202651,969062,37283.3%
Nov 9, 202648,470063,99575.7%
Nov 6, 202621,1061,48838,34255.0%
Nov 5, 2026119,92510,605182,77565.6%
Nov 4, 202671,7650104,57368.6%
Nov 3, 2026111,9510167,05667.0%
Nov 2, 202649,732081,32561.2%
Oct 30, 202624,581037,46265.6%
Oct 29, 202631,802044,95370.7%
Oct 28, 202650,1130108,78146.1%
Oct 27, 202656,5920111,51450.7%
Oct 26, 202642,462084,94750.0%
Oct 23, 202641,823074,31356.3%
Oct 22, 202699,037974184,33453.7%
Oct 21, 202637,314048,76076.5%
Oct 20, 2026128,9840138,01393.5%
Oct 19, 202643,026052,99781.2%
Oct 16, 202625,993041,53762.6%
Oct 15, 2026169,4030186,61090.8%
Oct 14, 202667,905079,64485.3%
Oct 13, 202669,6400100,68269.2%
Oct 12, 202620,956037,13356.4%
Oct 9, 202619,675040,56548.5%
Oct 8, 202622,850030,74574.3%
Oct 7, 202627,950045,52561.4%
Oct 6, 202628,525051,87355.0%
Oct 5, 202625,277039,86663.4%

ATS (dark pool) volume

Weekly volume on alternative trading systems (ATS) and other off-exchange (OTC) venues, from FINRA, for the last 12 weeks. ATS share is ATS volume ÷ (ATS + OTC volume), not a share of all trading.

Weekly ATS and OTC volume in KRRO
Week ofTierATS sharesATS tradesOther OTC sharesOther OTC tradesATS share
Oct 5, 2026T2135,5305,40079,4281,53763.0%
Sep 28, 2026T2142,6764,92762,1441,00669.7%
Sep 21, 2026T2182,4944,873133,5961,93657.7%
Sep 14, 2026T2409,8126,782382,2222,21851.7%
Sep 7, 2026T2192,0804,26442,54387381.9%
Aug 31, 2026T270,3884,78763,1341,75152.7%
Aug 24, 2026T261,7283,64339,6411,25260.9%
Aug 17, 2026T298,5095,18038,1231,17072.1%
Aug 10, 2026T2119,8594,67444,5111,03572.9%
Aug 3, 2026T2131,3115,25770,8121,14265.0%
Jul 27, 2026T2148,6357,82755,1201,15572.9%
Jul 20, 2026T2284,6507,06050,1911,14785.0%