Korro Bio (KRRO) CSO sells 3,418 shares to cover RSU taxes

Rhea-AI Filing Summary

Korro Bio, Inc. Chief Scientific Officer Vincent Loic A reported a sale of 3,418 shares of common stock at a weighted-average price of $10.83 per share. According to the disclosure, this was a mandatory sale solely to satisfy tax withholding obligations from vesting of a restricted stock unit granted under the 2023 Stock Option and Incentive Plan.

After this tax-related transaction, he holds 18,297 shares of common stock, including 10,858 shares issuable upon settlement of an RSU that is scheduled to vest on December 15, 2026, subject to continued service with the company.

Insider Trade Summary

Net Seller: 3,418 shares

Net Sell 1 txn

Insider Vincent Loic A

Role Chief Scientific Officer

Sold 3,418 shs ($37K)

Type	Security	Shares	Price	Value
Sale	Common Stock	3,418	$10.83	$37K

Holdings After Transaction: Common Stock — 18,297 shares (Direct)

Footnotes (3)

1. F1. Represents the mandatory sale of shares of common stock solely to satisfy tax withholding obligations incurred upon vesting and settlement of a restricted stock unit (RSU) granted under the Issuer's 2023 Stock Option and Incentive Plan (the 2023 Plan).
2. F2. The price reported in Column 4 is a weighted-average price. The shares were sold in multiple transactions at prices ranging from $10.58 to $11.35, inclusive. Full information regarding the number of shares sold at each separate price can be provided to the issuer, any security holder of the issuer or the staff of the Securities and Exchange Commission upon request.
3. F3. Includes 10,858 shares of common stock issuable upon settlement of a RSU granted under the 2023 Plan that will vest on December 15, 2026 subject to the reporting person maintaining a continuous Service Relationship (as defined in the 2023 Plan) through such date.

Key Figures

Shares sold: 3,418 shares Weighted-average sale price: $10.83 per share Shares held after transaction: 18,297 shares +1 more

4 metrics

Shares sold 3,418 shares Mandatory sale to satisfy tax withholding obligations from RSU vesting

Weighted-average sale price $10.83 per share Open-market transactions ranging from $10.58 to $11.35

Shares held after transaction 18,297 shares Total Korro Bio common stock held directly after tax-related sale

Unvested RSU shares 10,858 shares RSU under 2023 Plan scheduled to vest on December 15, 2026

Key Terms

restricted stock unit (RSU), 2023 Stock Option and Incentive Plan, weighted-average price, Service Relationship

4 terms

restricted stock unit (RSU) financial

"Represents the mandatory sale of shares of common stock solely to satisfy tax withholding obligations incurred upon vesting and settlement of a restricted stock unit (RSU)"

A restricted stock unit (RSU) is a promise from a company to give an employee company shares (or cash equal to their value) at a future date if certain conditions are met, such as staying with the company or hitting performance targets. For investors, RSUs matter because when they convert into actual shares they increase the number of shares available and can create selling pressure as employees cash out—think of them as a future paycheck paid in company stock.

2023 Stock Option and Incentive Plan financial

"restricted stock unit (RSU) granted under the Issuer's 2023 Stock Option and Incentive Plan (the 2023 Plan)"

weighted-average price financial

"The price reported in Column 4 is a weighted-average price. The shares were sold in multiple transactions"

Weighted-average price is the average of multiple prices where each price is counted according to its size or importance—larger trades carry more weight than smaller ones, like averaging course grades by credit hours. It matters to investors because it gives a more realistic picture of the true price paid or received, helping assess trade execution, compare performance, calculate cost basis, and value positions more accurately than a simple average.

Service Relationship financial

"will vest on December 15, 2026 subject to the reporting person maintaining a continuous Service Relationship"

FAQ

What did Korro Bio (KRRO) disclose about its Chief Scientific Officer's share sale?

Korro Bio reported that Chief Scientific Officer Vincent Loic A sold 3,418 common shares at a weighted-average price of $10.83. The filing explains the sale was mandatory to cover tax withholding from a restricted stock unit vesting under the company’s 2023 equity plan.

Was the Korro Bio (KRRO) insider sale a discretionary transaction?

No. The filing states the 3,418 shares sold by Chief Scientific Officer Vincent Loic A were a mandatory sale solely to satisfy tax withholding obligations triggered by vesting of a restricted stock unit granted under Korro Bio’s 2023 Stock Option and Incentive Plan.

How many Korro Bio (KRRO) shares does the Chief Scientific Officer hold after the transaction?

Following the tax-related sale, Chief Scientific Officer Vincent Loic A holds 18,297 shares of Korro Bio common stock. This total includes 10,858 shares issuable upon settlement of a restricted stock unit scheduled to vest on December 15, 2026, subject to continued service.

At what price were the Korro Bio (KRRO) shares sold in this Form 4 filing?

The reported price is a weighted-average of $10.83 per share for the 3,418 shares sold. The shares were sold in multiple transactions at prices ranging from $10.58 to $11.35, and detailed trade breakdowns are available from the company or regulators upon request.

What future vesting is disclosed for the Korro Bio (KRRO) Chief Scientific Officer's RSUs?

The filing notes that 10,858 shares of Korro Bio common stock are issuable upon settlement of a restricted stock unit. This RSU grant will vest on December 15, 2026, provided the Chief Scientific Officer maintains a continuous service relationship with the company through that date.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 06/17/2026 - 04:11 PM Accepted by SEC EDGAR 06/17/2026 - 04:11 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED 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^*

Vincent Loic A

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Scientific Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/16/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form 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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	06/16/2026		S(1)		3,418	D	$10.83(2)	18,297(3)	D

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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Represents the mandatory sale of shares of common stock solely to satisfy tax withholding obligations incurred upon vesting and settlement of a restricted stock unit (RSU) granted under the Issuer's 2023 Stock Option and Incentive Plan (the 2023 Plan).

2. The price reported in Column 4 is a weighted-average price. The shares were sold in multiple transactions at prices ranging from $10.58 to $11.35, inclusive. Full information regarding the number of shares sold at each separate price can be provided to the issuer, any security holder of the issuer or the staff of the Securities and Exchange Commission upon request.

3. Includes 10,858 shares of common stock issuable upon settlement of a RSU granted under the 2023 Plan that will vest on December 15, 2026 subject to the reporting person maintaining a continuous Service Relationship (as defined in the 2023 Plan) through such date.

	/s/ Jeffrey Cerio, Attorney-in-fact	06/17/2026
	** Signature of Reporting Person	Date
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)