KRRO on Nasdaq

Korro Bio, Inc.

We are a biopharmaceutical company with a mission to discover, develop and commercialize a new class of genetic medicines based on editing RNA, enabling the treatment of both rare and highly.3 From its latest annual report

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Last updated Oct 19, 2026.

Overview

Compare with KYNTRA BIO, INC., Heat Biologics or Immunome Inc., or pick any stock.

  • TickerKRRO on Nasdaq1
  • IndustryPharmaceutical Preparations1
  • HeadquartersCambridge, Massachusetts1
  • Incorporated inDE2
  • Business address60 First Street, 2Nd Floor, Suite 250, Cambridge, Ma 021412
  • Filer categoryNon-accelerated filer, Smaller reporting company2

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We are a biopharmaceutical company with a mission to discover, develop and commercialize a new class of genetic medicines based on editing RNA, enabling the treatment of both rare and highly prevalent diseases. We are generating a portfolio of differentiated programs that are designed to harness the body’s natural RNA editing process to effect a precise yet transient change to a single nucleoside (adenosine to an inosine edit). By editing RNA instead of DNA, we are expanding the reach of genetic medicines by delivering additional precision and tunability, which has the potential for increased specificity and improved long-term tolerability. We use an oligonucleotide-based approach and expect to bring our medicines to patients by leveraging our proprietary platform with precedented delivery modalities, including N-acetylgalactosamine, or GalNAc, -conjugated delivery for subcutaneous admin…3 From its latest annual report

Financials

From the company’s reports to the SEC. Every number links to the filing it came from.

Key numbers, fiscal 2025

-1906.4%Operating margin4
-1834.5%Net margin4
181.5%Revenue growth, 20254
-228.0%Return on equity4
-$79.1MFree cash flow4

Where the money goes

Where each dollar of revenue went, fiscal 2025

  • Research and development99¢$65.6M
  • Income tax1¢$637.0K

Out of $6.4M in revenue.4 The company lost money this year.

Financial statements

Revenue56784$6.4M in 2025−78% since 2019
0$10.0M$20.0M$30.0M$40.0M2019: $28.9M$28.9M20192020: $37.0M$37.0M2020+28%2021: $14.1M$14.1M2021−62%2022: $0$020222023: $0$020232024: $2.3M$2.3M20242025: $6.4M$6.4M2025+181%
Operating income567984-$121.9M in 2025+489% since 2019
-$150.0M-$100.0M-$50.0M02019: -$20.7M-$20.7M20192020: -$27.6M-$27.6M2020+33%2021: -$84.0M-$84.0M2021+205%2022: -$59.0M-$59.0M2022−30%2023: -$84.5M-$84.5M2023+43%2024: -$91.9M-$91.9M2024+9%2025: -$121.9M-$121.9M2025+33%
Net income567984-$117.3M in 2025+526% since 2019
-$150.0M-$100.0M-$50.0M02019: -$18.7M-$18.7M20192020: -$26.5M-$26.5M2020+41%2021: -$84.7M-$84.7M2021+219%2022: -$58.0M-$58.0M2022−31%2023: -$81.2M-$81.2M2023+40%2024: -$83.6M-$83.6M2024+3%2025: -$117.3M-$117.3M2025+40%

Every line of the income statement as filed: the last 2 fiscal years, latest first.4

Period ending2025-12-312024-12-31
Collaboration revenue$6.4M$2.3M
Research and development$65.6M$63.6M
General and administrative$28.2M$30.5M
Long-lived asset impairment charge$30.9M$0
Restructuring charge$3.6M$0
Total operating expenses$128.2M$94.2M
Loss from operations-$121.9M-$91.9M
Other income, net$5.2M$8.5M
Total other income, net$5.2M$8.5M
Loss before provision for income taxes-$116.6M-$83.4M
Provision for income taxes-$637.0K-$141.0K
Net loss-$117.3M-$83.6M
Unrealized (loss) gain on available-for-sale marketable securities-$26.0K$184.0K
Foreign currency translation adjustments, net-$30.0K$84.0K
Comprehensive loss-$117.3M-$83.3M
Net loss per share, basic-$12.48-$9.37
Net loss per share, diluted-$12.48-$9.37
Weighted-average shares used in computing net loss per share, basic9.4M shares8.9M shares
Weighted-average shares used in computing net loss per share, diluted9.4M shares8.9M shares

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Leadership

Who has led Korro Bio, Inc., and when. Pick a name to see everywhere that person has worked.

Chief executive

  1. David L. Lucchino2019–2023
  2. Ram Aiyar2023–now

President

  1. David L. Lucchino2019–2023
  2. Ram Aiyar2023–now

Chief financial officer

  1. Peter P. Pfreundschuh2020–2022
  2. Vineet Agarwal2023–2025

Chief operating officer

  1. Todd Chappell2023–now
20202025
Board members and other officers (27)

Former names

  • Frequency Therapeutics, Inc.Apr 14, 2017 to Nov 6, 20232

Timeline

  1. Nov 7, 2023New chief executive Ram Aiyar becomes CEO12
  2. Oct 2, 2019New chief executive David L. Lucchino becomes CEO13

Filings

615 filings to the SEC since October 2021: 6 annual reports, 15 quarterly reports, 68 major events, 219 insider forms, 49 large holders, 258 other. The latest 20:

  1. Oct 5, 20268-K EDGAR
  2. Sep 15, 20264 EDGAR
  3. Sep 14, 2026144 EDGAR
  4. Sep 14, 2026144 EDGAR
  5. Sep 14, 20264 EDGAR
  6. Sep 11, 2026144 EDGAR
  7. Sep 11, 2026144 EDGAR
  8. Sep 11, 2026144 EDGAR
  9. Sep 10, 20264 EDGAR
  10. Sep 9, 2026144 EDGAR
  11. Sep 8, 2026144 EDGAR
  12. Aug 28, 20264 EDGAR
  13. Aug 26, 2026144 EDGAR
  14. Aug 26, 2026144 EDGAR
  15. Aug 21, 20264 EDGAR
  16. Aug 19, 2026144 EDGAR
  17. Aug 19, 2026144 EDGAR
  18. Aug 19, 20268-K EDGAR
  19. Aug 14, 2026SCHEDULE 13G/A EDGAR
  20. Aug 13, 20264 EDGAR

The 615 filings since October 2021 can be filtered by form type and year here when JavaScript is on.

Every filing from the last five years, summarized. The full record is on SEC EDGAR.

Insider trades

168 open-market trades by officers, directors and large owners since October 2021: 22 buys and 146 sales. Grants, option exercises and gifts are left out.

DateWhoTradeSharesPriceValueFiling
Sep 14, 2026FORMELA JEAN FRANCOISDirectorSale38,490$14.12$543.5KForm 4
Sep 11, 2026Dolan OliverSenior Vice President, FinanceSale5$13.72$69Form 4
Sep 11, 2026FORMELA JEAN FRANCOISDirectorSale10,200$13.99$142.7KForm 4
Sep 9, 2026Dolan OliverSenior Vice President, FinanceSale6$13.60$82Form 4
Sep 8, 2026Dolan OliverSenior Vice President, FinanceSale7,347$13.51$99.3KForm 4
Aug 26, 2026FORMELA JEAN FRANCOISDirectorSale300$13.96$4.2KForm 4
Aug 19, 2026FORMELA JEAN FRANCOISDirectorSale28,468$14.00$398.6KForm 4
Aug 11, 2026FORMELA JEAN FRANCOISDirectorSale2,143$13.96$29.9KForm 4
Aug 10, 2026Lynx1 Capital Management LP10% ownerBuy1,462$13.19$19.3KForm 4
Aug 6, 2026Lynx1 Capital Management LP10% ownerBuy5,222$11.40$59.5KForm 4
Aug 4, 2026Aiyar RamPresident and CEOSale5,802$10.84$62.9KForm 4
Jul 6, 2026FORMELA JEAN FRANCOISDirectorSale9,323$13.96$130.1KForm 4
Jul 2, 2026FORMELA JEAN FRANCOISDirectorSale100,700$14.03$1.4MForm 4
Jun 24, 2026FORMELA JEAN FRANCOISDirectorSale48,438$14.61$707.5KForm 4
Jun 23, 2026FORMELA JEAN FRANCOISDirectorSale119,005$14.25$1.7MForm 4
Jun 22, 2026FORMELA JEAN FRANCOISDirectorSale3,962$13.95$55.3KForm 4
Jun 16, 2026Chappell ToddChief Operating OfficerSale3,168$10.83$34.3KForm 4
Jun 16, 2026Vincent Loic AChief Scientific OfficerSale3,418$10.83$37.0KForm 4
Jun 16, 2026Cerio JeffreyGeneral CounselSale6,609$10.83$71.6KForm 4
Jun 16, 2026Dolan OliverSenior Vice President, FinanceSale3,383$10.83$36.6KForm 4

All 168 trades can be filtered by person here when JavaScript is on.

From Forms 4 filed with the SEC.

Major holders

Investors who own more than 5% of the shares must tell the SEC: a 13D if they may seek to influence the company, a 13G if they hold passively.

Held by these funds

The largest holders among investment managers' 13F reports for the quarter ending Jun 30, 2026, the top 25 of 100. Change is in shares since the quarter before.

FundSharesValueShare of the fundChange
Lynx1 Capital Management LP1,538,296$20.3M2.3%No change
Nantahala Capital Management, LLC1,320,072$17.4M0.5%+660,036
NEA Management Company, LLC1,297,893$17.1M1.1%No change
Venrock Adviser, LLC1,009,500$13.3M0.4%No change
Atlas Venture Life Science Advisors, LLC962,884$12.7M1.4%−174,265
Balyasny Asset Management L.P.951,783$12.5M0.0%−88,271
BlackRock, Inc.817,621$10.8M0.0%+357,615
Affinity Asset Advisors, LLC706,904$9.3M0.5%No change
Adage Capital Partners Gp, L.l.c.540,968$7.1M0.0%+312,568
ADAR1 Capital Management, LLC540,054$7.1M0.3%No change
Vanguard Capital Management LLC454,778$6.0M0.0%+143,865
Driehaus Capital Management LLC450,045$5.9M0.0%No change
TCG Crossover Management, LLC416,301$5.5M0.1%No change
Kalehua Capital Management LLC405,040$5.3M1.7%+295,664
Siren, L.L.C.347,718$4.6M0.1%No change
Aqr Capital Management LLC298,974$3.9M0.0%+31,219
Geode Capital Management, LLC296,870$3.9M0.0%+123,227
72 Investment Holdings, LLC276,831$3.6M7.3%No change
State Street Corp232,587$3.1M0.0%+92,246
Vanguard Portfolio Management LLC223,551$2.9M0.0%+74,992
Two Sigma Investments, LP178,071$2.3M0.0%+12,599
Jpmorgan Chase & Co124,726$1.6M0.0%+56,226
Millennium Management LLC118,434$1.6M0.0%+54,828
Goldman Sachs Group Inc116,983$1.5M0.0%+66,442
Renaissance Technologies LLC110,524$1.5M0.0%−25,703

13F reports cover disclosed long positions in U.S. stocks only.

Sources

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