STOCK TITAN

Korro Bio (KRRO) CEO gains 50,000 shares from PSU vesting and RSUs

Filing Impact
(Very High)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Korro Bio, Inc. President and CEO Ram Aiyar reported an equity award that increased his beneficial holdings. On May 26, 2026, he acquired 50,000 shares of common stock at $12.33 per share, issued upon settlement and vesting of a performance stock unit granted under the company’s 2023 Stock Option and Incentive Plan.

Following this transaction, he beneficially owns 90,000 shares directly, which includes 40,000 shares issuable upon settlement of a previously reported restricted stock unit grant. An additional 4,613 shares are held indirectly by The Ram Aiyar Irrevocable Trust, for which he serves as trustee and disclaims beneficial ownership except to the extent of his pecuniary interest.

Positive

  • None.

Negative

  • None.
Insider Aiyar Ram
Role President and CEO
Type Security Shares Price Value
Grant/Award Common Stock 50,000 $12.33 $617K
holding Common Stock -- -- --
Holdings After Transaction: Common Stock — 90,000 shares (Direct, null); Common Stock — 4,613 shares (Indirect, Shares are held by The Ram Aiyar Irrevocable Trust.)
Footnotes (1)
  1. Represents shares of common stock issued upon settlement and vesting of a performance stock unit (PSU) granted under the Issuer's 2023 Stock Option and Incentive Plan (the 2023 Plan) that vested and settled upon achievement of the performance condition on May 26, 2026. Includes 40,000 shares of common stock issuable upon settlement of a restricted stock unit granted under the 2023 Plan as reported on Form 4 dated February 3, 2026. Shares held by The Ram Aiyar Irrevocable Trust, for which the Reporting Person serves as trustee. The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.
Shares acquired via PSU vesting 50,000 shares Common Stock issued upon PSU settlement on May 26, 2026
Recorded transaction price $12.33 per share Price per share for 50,000-share non-derivative acquisition
Direct beneficial holdings after transaction 90,000 shares Includes 40,000 shares issuable upon RSU settlement
RSU-linked shares included in total 40,000 shares Common stock issuable upon settlement of restricted stock unit
Indirect trust holdings 4,613 shares Common Stock held by The Ram Aiyar Irrevocable Trust
Acquire-type transactions in this filing 1 transaction Grant/award acquisition in transaction summary
performance stock unit (PSU) financial
"Represents shares of common stock issued upon settlement and vesting of a performance stock unit (PSU) granted under the Issuer's 2023 Stock Option and Incentive Plan"
restricted stock unit financial
"Includes 40,000 shares of common stock issuable upon settlement of a restricted stock unit granted under the 2023 Plan"
A restricted stock unit is a promise from a company to give an employee shares of stock after certain conditions are met, like staying with the company for a set amount of time. It’s like earning a bonus that turns into company stock once you’ve proven your commitment, making it a way to motivate and reward employees.
2023 Stock Option and Incentive Plan financial
"granted under the Issuer's 2023 Stock Option and Incentive Plan (the 2023 Plan)"
pecuniary interest financial
"disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein"
Section 16 regulatory
"shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose"
Section 16 is a U.S. securities law rule that governs the trading and disclosure obligations of company insiders — typically officers, directors and large shareholders — to promote transparency and deter unfair profit-taking. It requires insiders to publicly report their stock trades and allows companies or the issuer to reclaim quick, short-term profits from certain insider trades, like a scoreboard and a refund policy that help investors see and limit possible insider advantage.
SEC Form 4
FORM 4UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
Aiyar Ram

(Last)(First)(Middle)
C/O KORRO BIO, INC.
60 FIRST STREET, 2ND FLOOR, SUITE 250

(Street)
CAMBRIDGE MASSACHUSETTS 02141

(City)(State)(Zip)

UNITED STATES

(Country)
2. Issuer Name and Ticker or Trading Symbol
Korro Bio, Inc. [ KRRO ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirector10% Owner
XOfficer (give title below)Other (specify below)
President and CEO
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
05/26/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year)2A. Deemed Execution Date, if any (Month/Day/Year)3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeVAmount(A) or (D)Price
Common Stock(1)05/26/2026A50,000(1)A$12.3390,000(2)D
Common Stock4,613IShares are held by The Ram Aiyar Irrevocable Trust.(3)
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year)3A. Deemed Execution Date, if any (Month/Day/Year)4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year)7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
1. Represents shares of common stock issued upon settlement and vesting of a performance stock unit (PSU) granted under the Issuer's 2023 Stock Option and Incentive Plan (the 2023 Plan) that vested and settled upon achievement of the performance condition on May 26, 2026.
2. Includes 40,000 shares of common stock issuable upon settlement of a restricted stock unit granted under the 2023 Plan as reported on Form 4 dated February 3, 2026.
3. Shares held by The Ram Aiyar Irrevocable Trust, for which the Reporting Person serves as trustee. The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.
/s/ Jeffrey Cerio, Attorney-in-fact05/28/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What did Korro Bio (KRRO) CEO Ram Aiyar report in this Form 4?

Ram Aiyar reported acquiring 50,000 Korro Bio common shares through performance stock unit vesting. These shares were issued under the 2023 Stock Option and Incentive Plan after a performance condition was achieved on May 26, 2026, increasing his reported beneficial holdings.

How many Korro Bio (KRRO) shares does the CEO hold after this transaction?

After the transaction, Ram Aiyar is reported as beneficially owning 90,000 shares directly. This figure includes 40,000 shares of common stock issuable upon settlement of a previously granted restricted stock unit under the company’s 2023 equity incentive plan.

What is the origin of the 50,000 Korro Bio (KRRO) shares acquired by the CEO?

The 50,000 shares were issued upon settlement and vesting of a performance stock unit granted under Korro Bio’s 2023 Stock Option and Incentive Plan. The award vested and settled when a specified performance condition was achieved on May 26, 2026, triggering share issuance.

At what price were the new Korro Bio (KRRO) shares recorded in the Form 4?

The Form 4 records the 50,000 newly issued common shares at $12.33 per share. This price appears as the transaction price per share associated with the equity award settlement reported on May 26, 2026, in the non-derivative transaction table.

What Korro Bio (KRRO) shares are held through The Ram Aiyar Irrevocable Trust?

The filing shows 4,613 Korro Bio common shares held indirectly by The Ram Aiyar Irrevocable Trust. Ram Aiyar serves as trustee and disclaims beneficial ownership of these securities except to the extent of his pecuniary interest, as described in the Form 4 footnote.

What additional unissued Korro Bio (KRRO) shares are included in the CEO’s reported holdings?

The Form 4 states that the 90,000-share figure includes 40,000 shares of common stock issuable upon settlement of a restricted stock unit grant. This restricted stock unit was granted under the 2023 Stock Option and Incentive Plan and reported previously in a February 3, 2026 filing.