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Korro Bio

KRRO on Nasdaq. Pharmaceutical preparations. Market value $147m.

Watch this stockFree. We tell you when something changes.

Should I look at this?

Not a fit for our list right now

Why it could be worth it

What to watch out for

See Health care stocks that passed both tests

This is not advice. Check the numbers below.

Compare with another stock

Cash yield
-53.6%low

For every $100 of what the whole company costs, it produced $-53.59 of spare cash last year. A savings account pays about $4.

Price to profit
n/a

The filings do not give us enough to work this out.

Return on capital
n/a

The filings do not give us enough to work this out.

Quality score: 33 of 100. Price score: 0 of 100. Our list needs 70 on quality and 60 on price.

Five years of cash, in billions

-0.1
-0.1
-0.1
202320242025
Revenue
$0$2m$6m
Operating margin
n/a-4047.1%-1906.4%
Debt to equity
n/an/an/a
Shares outstanding
0.04bn0.01bn0.01bn

Health checks

  • Free cash flow positive0 of 5 years
  • Accounting checksSkipped: company is not yet profitable
  • Debt0.00× equity
  • Revenue growth, five yearsUnknown
  • Buying back its own sharesYes, 73% fewer since 2023

Dates

Next results (estimated)
n/a
Last annual report (10-K)
12 March 2026
Next quarterly (estimated, 10-Q)
5 November 2026

Who owns it

None of the long-term investors we follow own it. 107 funds in all.

Jun '25
Dec '25
Jun '26
Largest holders overall

From 13F filings for the quarter ended 30 June 2026.

Big holders and activists

10 investors own more than 5%.

  • at least 10.7%+2.9 pts
    (filed with 1 related holder)
    Since 31 March 2026
  • Venrock Healthcare Capital Partners III, L.P.
    Passive investor
    at least 9.9%
    (filed with 6 related holders)
    Since 10 March 2026
  • New Enterprise Associates 17, L.P.
    Passive investor
    at least 9.9%
    (filed with 11 related holders)
    Since 10 March 2026
    What they said

    NEA 17 acquired the NEA 17 Shares for investment purposes. Information with respect to the 2026 Private Placement set forth in Item 3 above is incorporated herein by reference to the extent responsive to this Item 4. Subject to the Registration Rights Agreement, the 2024…

    Read the filing
  • at least 6.6%−0.6 pts
    (filed with 4 related holders)
    Since 30 June 2026
  • at least 6.4%
    (filed with 2 related holders)
    Since 31 December 2025
  • BlackRock, Inc.
    Passive investor
    5.2%
    Since 30 June 2026
  • Atlas Venture Fund XI, L.P.
    Passive investor
    at least 4.9%
    (filed with 5 related holders)
    Since 24 June 2026
  • Citadel Advisors LLC
    Passive investor
    at least 3.9%
    (filed with 6 related holders)
    Since 31 December 2024
  • Deep Track Capital, LP
    Passive investor
    at least 3.0%
    (filed with 2 related holders)
    Since 30 June 2025
  • Point72 Biotech Private Investments, LLC
    Passive investor
    at least 1.9%−3.8 pts
    (filed with 5 related holders)
    Since 31 March 2026
  • FMR LLC
    Passive investor
    Sold down below 5%
    Since 31 December 2025
  • AllianceBernstein L.P.
    Passive investor
    Sold down below 5%
    Since 30 June 2025
  • The Vanguard Group
    Passive investor
    Sold down below 5%
    Since 13 March 2026
  • Sold down below 5%
    Since 31 December 2025

From Schedule 13D and 13G filings: anyone owning more than 5% must file one.

What insiders did

No insider bought shares on the open market in the last 12 months. 6 sold $6m, $5m of it under preset trading plans.

  • FORMELA JEAN FRANCOIS
    Director
    Sold
    under a preset trading plan
    Date
    14 September 2026
    Shares
    38,490
    Price
    $14.12
    Value
    $543,479
  • FORMELA JEAN FRANCOIS
    Director
    Sold
    under a preset trading plan
    Date
    11 September 2026
    Shares
    10,200
    Price
    $13.99
    Value
    $142,698
  • Dolan Oliver
    Senior Vice President, Finance
    Sold
    under a preset trading plan
    Date
    11 September 2026
    Shares
    5
    Price
    $13.72
    Value
    $69
  • Dolan Oliver
    Senior Vice President, Finance
    Sold
    under a preset trading plan
    Date
    9 September 2026
    Shares
    6
    Price
    $13.60
    Value
    $82
  • Dolan Oliver
    Senior Vice President, Finance
    Sold
    under a preset trading plan
    Date
    8 September 2026
    Shares
    7,347
    Price
    $13.51
    Value
    $99,286
  • FORMELA JEAN FRANCOIS
    Director
    Sold
    under a preset trading plan
    Date
    26 August 2026
    Shares
    300
    Price
    $13.96
    Value
    $4,188
  • FORMELA JEAN FRANCOIS
    Director
    Sold
    under a preset trading plan
    Date
    19 August 2026
    Shares
    28,468
    Price
    $14.00
    Value
    $398,552
  • FORMELA JEAN FRANCOIS
    Director
    Sold
    under a preset trading plan
    Date
    11 August 2026
    Shares
    2,143
    Price
    $13.96
    Value
    $29,916
  • Aiyar Ram
    President and CEO, Director
    Sold
    Date
    4 August 2026
    Shares
    5,802
    Price
    $10.84
    Value
    $62,917
  • FORMELA JEAN FRANCOIS
    Director
    Sold
    under a preset trading plan
    Date
    6 July 2026
    Shares
    9,323
    Price
    $13.96
    Value
    $130,149

From Form 4 filings: insiders must report trades in their own company's shares within two days.

Warning signs in its filings

Problems the company itself reported to the SEC, in its own words.

None of the warning signs we check for were found.

We look for five warning signs: doubt it can keep going, weak checks on its own accounts, a notice that its past accounts can't be relied on, a change of auditor, and one customer bringing in a big share of sales. We don't check lawsuits, investigations or debt yet.

We checked the auditor's report, internal controls, restatement notices, auditor changes and big customers in the 10-K filed 12 Mar 2026, plus the 10-Q filed 6 Aug 2026 and 6 later 8-Ks.

A 10-K is the yearly report every US company files with the SEC. An 8-K is a short notice of a big event.

What could go wrong

Cheap for a reason is the question the numbers cannot answer.

Whether the price already reflects the risks is what the deep dive is for.

The deep dive

Everything above is arithmetic on public filings. The deep dive reads the last ten years of annual reports, the proxy statements, and the earnings calls, then argues the case the way Buffett, Klarman, and Hohn would, and checks every claim against the source.

  • What the business is worth, as a range, and the margin of safety at today’s price
  • Prices to start buying, buy, and buy hard
  • The three things that would make this a mistake
  • Every number footnoted to the filing it came from
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What a finished deep dive looks like

Not advice. Numbers on this page come from SEC filings and are updated each night; prices are updated again after the US market closes. The five-year figures are rounded.