Korro Bio (KRRO) boosts Jeffrey Cerio salary, severance and RSU grant

Rhea-AI Filing Summary

Korro Bio updated the employment agreement for executive Jeffrey Cerio, effective December 15, 2025. His new agreement keeps most prior terms but raises his annual base salary to $425,000. It also increases his cash severance from six to nine months of salary if he is terminated without cause or resigns for good reason, and from nine to 12 months if this occurs within a change in control period.

As part of a broader employee appreciation and retention program, Dr. Cerio will receive a $100,000 cash bonus, paid in two equal installments on December 31, 2025 and on or about June 30, 2026, subject to continued service. He was also granted 41,902 restricted stock units under Korro’s 2023 Stock Option and Incentive Plan, vesting 50% on June 15, 2026 and 50% on December 15, 2026, contingent on continued service through each vesting date.

8-K Event Classification

2 items: 5.02, 9.01

2 items

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers Governance

Key personnel changes including departures, elections, or appointments of directors and executive officers.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, and exhibit attachments filed with this report.

Understanding 8-K Material Events →

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): December 15, 2025

Korro Bio, Inc.

(Exact name of registrant as specified in its charter)

Delaware	001-39062	47-2324450
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)
60 First Street, 2nd floor, Suite 250 Cambridge, MA		02141
(Address of principal executive offices)		(Zip Code)

Registrant’s telephone number, including area code: (617) 468-1999

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common stock, par value $0.001 per share		KRRO		The Nasdaq Capital Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Effective December 15, 2025, Korro Bio, Inc., or Korro, entered into an amended and restated employment agreement with Jeffrey Cerio, which amended and restated his employment agreement dated August 28, 2024.

Dr. Cerio’s new employment agreement is substantially consistent with the terms of his prior employment agreement as described in Korro’s definitive proxy statement on Schedule 14A filed on April 29, 2025, although it provides for (i) increased annual base salary of $425,000 (reflecting current 2025 base salary); (ii) increased severance from six months to nine months in connection with a termination without cause or resignation for good reason and (iii) increased severance from nine to 12 months of his then-current salary in connection with a termination without cause or resignation for good reason within the change in control period.

As part of a broader employee appreciation and retention program, Dr. Cerio was (i) awarded a $100,000 cash bonus, 50% of which will be paid on December 31, 2025, and 50% of which will be paid on or about June 30, 2026, in each case subject to Dr. Cerio maintaining a continuous service relationship through each such payment date and (ii) granted an equity award of 41,902 restricted stock units, or RSUs, effective December 15, 2025 under Korro’s 2023 Stock Option and Incentive Plan (or the 2023 Plan). The RSUs vest as to 50% on June 15, 2026, and as to the remaining 50% on December 15, 2026, in each case subject to Dr. Cerio maintaining a continuous service relationship as defined in the 2023 Plan through each such vesting date.

The foregoing summary of Dr. Cerio’s amended and restated employment agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the agreement, a copy of which is filed as Exhibit 10.1 to this Current Report on Form 8-K and incorporated by reference herein.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.		Description
10.1#		Amended and Restated Employment Agreement with Jeffrey Cerio, dated effective December 15, 2025
104		Cover Page Interactive Data File (embedded within the Inline XBRL document)

# Indicates a management contract or any compensatory plan, contract or arrangement.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	KORRO BIO, INC.
Date: December 18, 2025	By:	/s/ Ram Aiyar
		Name: Ram Aiyar
		Title: President and Chief Executive Officer and Interim Chief Financial Officer

FAQ

What executive compensation change did Korro Bio (KRRO) disclose for Jeffrey Cerio?

Korro Bio disclosed that Dr. Jeffrey Cerio entered into an amended and restated employment agreement effective December 15, 2025, which is largely consistent with his prior agreement but includes an increased annual base salary of $425,000 and enhanced severance protections.

How did Korro Bio (KRRO) change severance terms for Dr. Cerio?

Dr. Cerio’s severance increased from six to nine months of salary for a termination without cause or resignation for good reason, and from nine to 12 months of then-current salary if such a termination occurs within a change in control period.

What bonus is Dr. Jeffrey Cerio receiving under Korro Bios appreciation program?

As part of an employee appreciation and retention program, Dr. Cerio was awarded a $100,000 cash bonus, with 50% payable on December 31, 2025 and 50% on or about June 30, 2026, in each case conditioned on his continued service through the payment date.

What equity award did Korro Bio (KRRO) grant to Dr. Cerio?

Korro Bio granted Dr. Cerio an equity award of 41,902 restricted stock units (RSUs) under its 2023 Stock Option and Incentive Plan, effective December 15, 2025.

When do Dr. Cerios new RSUs from Korro Bio vest?

The 41,902 RSUs vest in two equal tranches: 50% on June 15, 2026 and the remaining 50% on December 15, 2026, provided he maintains a continuous service relationship through each vesting date.

Where can investors find the full text of Dr. Cerios amended employment agreement with Korro Bio (KRRO)?

The full text of Dr. Cerios amended and restated employment agreement is filed as Exhibit 10.1 to this report and is incorporated by reference.