[Form 4] Kronos Bio, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Form 4 snapshot: Kronos Bio (KRON) director Elena Ridloff reported the disposal of her remaining equity on 20 Jun 2025 following the closing of the company’s merger with Concentra Biosciences. She tendered 25,296 common shares, each exchanged for $0.57 in cash plus one contingent value right (CVR), matching the terms of the tender offer that closed on 18 Jun 2025. All of Ridloff’s outstanding stock options—covering 136,200 shares with strike prices between $0.95 and $24.18—were automatically cancelled because every exercise price exceeded the $0.57 cash component, so no additional consideration was received. After these transactions she holds zero shares or options, and Kronos Bio is now a wholly owned subsidiary of Concentra Biosciences.

Positive

• Merger consideration confirmed: Shareholders (including insiders) received $0.57 in cash plus a CVR for each Kronos Bio share, providing definitive liquidity.

Negative

• None.

Insights

Securities Analyst

TL;DR: Filing confirms director’s exit position; reflects merger completion, cash payout of $0.57 + CVR, no fresh valuation signal.

The Form 4 is largely administrative. It reiterates previously announced deal economics—$0.57 per share cash and a CVR—now applied to a single insider’s holdings. Option cancellation indicates strike prices above the cash consideration, implying those instruments were far out-of-the-money. Because the merger terms were public since 1 May 2025, today’s disclosure adds little incremental information and should not move the market. It does, however, confirm final settlement mechanics and that insiders no longer retain equity, eliminating potential overhang.

Corporate Governance Expert

TL;DR: Director’s Form 4 finalizes equity disposition under merger; governance transition to new parent complete.

This filing shows clean termination of insider ownership concurrent with Kronos Bio becoming a private, wholly owned subsidiary of Concentra Biosciences. The automatic vest-and-cancel treatment of options follows standard M&A practice when strike prices exceed deal value, limiting windfalls and aligning payouts with shareholders. With no remaining insider stakes, legacy board influence over the public entity ceases, paving the way for parent-level governance. From a compliance perspective, the report meets Section 16 obligations and signals that Form 4/5 filing requirements will likely cease going forward.

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
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X

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^*

Ridloff Elena

(Last) (First) (Middle)

C/O KRONOS BIO, INC.

301 BINNEY STREET, 2ND FLOOR EAST

(Street)

CAMBRIDGE MA 02142

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Kronos Bio, Inc. [ KRON ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

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

3. Date of Earliest Transaction (Month/Day/Year)
06/20/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

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

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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	06/20/2025		U		25,296(1)(2)	D	$0.57	0	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
Stock Option (Right to Buy)	$13.346	06/20/2025		D			25,879	(3)	09/10/2030	Common Stock	25,879	$0	0	D
Stock Option (Right to Buy)	$13.346	06/20/2025		D			26,871	(3)	09/10/2030	Common Stock	26,871	$0	0	D
Stock Option (Right to Buy)	$24.18	06/20/2025		D			15,450	(3)	06/21/2031	Common Stock	15,450	$0	0	D
Stock Option (Right to Buy)	$3.53	06/20/2025		D			34,000	(3)	06/21/2032	Common Stock	34,000	$0	0	D
Stock Option (Right to Buy)	$1.48	06/20/2025		D			17,000	(3)	06/21/2033	Common Stock	17,000	$0	0	D
Stock Option (Right to Buy)	$0.95	06/20/2025		D			17,000	(3)	06/24/2034	Common Stock	17,000	$0	0	D

Explanation of Responses:

1. Disposed of pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of May 1, 2025, by and among Kronos Bio, Inc. (the "Issuer"), Concentra Biosciences, LLC ("Parent") and Concentra Merger Sub IV, Inc., a wholly owned subsidiary of Parent ("Merger Sub"). On June 18, 2025, Parent and Merger Sub completed a tender offer pursuant to the terms of the Merger Agreement for all outstanding shares of common stock of the Issuer (each, a "Share") for an offer price of (i) $0.57 per Share in cash (the "Cash Amount"), and (ii) one non-transferable contractual contingent value right (each, a "CVR"), subject to and in accordance with the terms of the Contingent Value Rights Agreement (the "CVR Agreement"), in each case, without interest, and subject to any applicable withholding taxes (the Cash Amount plus one CVR, collectively, the "Offer Price").[continues to Footnote 2]

2. [continues from Footnote 1] Merger Sub thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Parent (the "Merger"). At the effective time of the Merger, each issued and outstanding Share (other than any Excluded Shares (as such term is defined in the Merger Agreement)) was cancelled in exchange for the right to receive the Offer Price.

3. As of immediately prior to and conditioned upon the effective time of the effective time of the Merger, pursuant to the Merger Agreement, each outstanding option to purchase Shares (each, an "Option") became fully vested and exercisable, and to the extent not exercised prior to the effective time of the Merger, was cancelled and converted into the right to receive (a) an amount in cash (without interest and subject to deduction for any required withholding tax) equal to the product of (1) the excess, if any, of the Cash Amount over the exercise price per share of each such Option and (2) the number of Shares underlying such Option immediately prior to the effective time of the Merger and (b) one CVR in respect of each Share underlying such Option; provided, however, that if the exercise price per Share of any Option was equal to or greater than the Cash Amount that was then outstanding it was cancelled for no consideration.

	/s/ Elena Ridloff	06/20/2025
	** 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.
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FAQ

What did Kronos Bio (KRON) director Elena Ridloff report in this Form 4?

She disposed of 25,296 common shares and all outstanding stock options as part of the merger closing.

What price did Ridloff receive for each KRON share?

$0.57 in cash plus one non-transferable contingent value right (CVR).

Were any of the director’s stock options exercised?

No. All options had exercise prices above $0.57 and were cancelled for no consideration.

When was the merger with Concentra Biosciences completed?

The tender offer closed on 18 Jun 2025 and the merger became effective shortly thereafter.

Does the director hold any Kronos Bio equity after these transactions?

No. Her beneficial ownership is now zero shares and options.