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

Rhea-AI Filing Summary

Key event: Form 4 discloses that director David M. Tanen has disposed of 100 % of his equity position in Kronos Bio (KRON) on 20 June 2025.

The disposition covers 887,408 common shares (363,428 held directly and 523,980 held through a revocable trust and family members) at the previously announced tender-offer cash price of $0.57 per share plus one non-transferable contingent value right (CVR) per share. All positions are now reported as zero.

Simultaneously, 227,100 stock options with exercise prices ranging from $0.95 to $24.18 were cancelled pursuant to the merger terms. Options with strike prices below $0.57 became fully vested and entitled the holder to a cash-out equal to the intrinsic value (cash amount minus exercise price) plus one CVR per underlying share; options that were at or above $0.57 received no consideration.

The transactions were executed in accordance with the Agreement and Plan of Merger dated 1 May 2025 among Kronos Bio, Concentra Biosciences, and Merger Sub IV. Concentra completed the tender offer on 18 June 2025 and immediately merged with Kronos Bio, which now operates as a wholly owned subsidiary of Concentra. At the effective time, all outstanding Kronos Bio shares (other than excluded shares) were cancelled and converted into the right to receive the offer price.

Following these actions, Mr. Tanen is no longer a beneficial owner of Kronos Bio securities, and Section 16 insider reporting obligations for this issuer will cease unless he acquires new positions.

Positive

• Confirmation of merger completion: Filing validates that Concentra’s acquisition of Kronos Bio has closed and cash consideration was delivered as planned.
• Equal treatment of insiders and public shareholders: Insider received the same $0.57 cash plus CVR package, indicating no preferential terms.

Negative

• Cancellation of out-of-the-money options: Several option grants with exercise prices ≥ $0.57 were terminated for no consideration, eliminating potential upside for the insider.
• Insider no longer holds shares: Director’s ownership falls to zero, removing alignment with any future CVR or legacy equity performance.

Insights

Securities Analyst

TL;DR: Insider exits all KRON holdings as merger completes; cash paid at $0.57 plus CVR, options cancelled per terms.

The Form 4 confirms the closing mechanics of Kronos Bio’s sale to Concentra Biosciences. All insider common shares—roughly 887 k—were tendered at $0.57, matching the public offer. The filing removes residual uncertainty about insider retention or post-merger stakes. Options with strikes below $0.57 generated limited cash value; those at or above the cash amount were cancelled without payment, illustrating that much of management’s option package was out-of-the-money. Overall, the disclosure is a procedural endpoint rather than a performance signal, but it affirms that minority shareholders received identical treatment to insiders.

M&A Specialist

TL;DR: Filing evidences final step of tender-offer/merger process; director’s holdings zeroed, confirming deal consummation.

The document provides granular proof that the May 1 Merger Agreement reached full closure. Payment terms—$0.57 cash plus CVR—were executed uniformly across direct, trust, and family accounts, and all derivative instruments were settled or extinguished as specified. Such filings are routine yet important: they start the statute of limitations clock for dissent claims and demonstrate compliance with Rule 10b5-1. From an investor lens, the impact is largely absorbed; trading in KRON will soon cease, and residual value rests solely in the CVR, whose economics are not detailed here. Impact rating is neutral because no new economic consideration is introduced beyond previously published terms.

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

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^*

TANEN DAVID M

(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		363,428(1)(2)	D	$0.57	0	D
Common Stock	06/20/2025		U		471,230(1)(2)	D	$0.57	0	I	See Footnote(3)
Common Stock	06/20/2025		U		26,375(1)(2)	D	$0.57	0	I	By Son
Common Stock	06/20/2025		U		26,375(1)(2)	D	$0.57	0	I	By Son
Common Stock	06/20/2025		U		26,375(1)(2)	D	$0.57	0	I	By Daughter

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)	$4.1422	06/20/2025		D			85,608	(4)	07/09/2030	Common Stock	85,608	$0	0	D
Stock Option (Right to Buy)	$4.1422	06/20/2025		D			19,892	(4)	07/09/2030	Common Stock	19,892	$0	0	D
Stock Option (Right to Buy)	$24.18	06/20/2025		D			20,600	(4)	06/21/2031	Common Stock	20,600	$0	0	D
Stock Option (Right to Buy)	$3.53	06/20/2025		D			34,000	(4)	06/21/2032	Common Stock	34,000	$0	0	D
Stock Option (Right to Buy)	$1.48	06/20/2025		D			34,000	(4)	06/21/2033	Common Stock	34,000	$0	0	D
Stock Option (Right to Buy)	$0.95	06/20/2025		D			34,000	(4)	06/24/2034	Common Stock	34,000	$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. By the David Tanen Revocable Grantor Trust.

4. 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/ David M.Tanen	06/20/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What amount of Kronos Bio (KRON) shares did David M. Tanen dispose of?

He disposed of 887,408 common shares (direct and indirect combined) on 20 Jun 2025.

At what price were KRON shares tendered in the Concentra Biosciences merger?

Each share was exchanged for $0.57 in cash plus one contingent value right (CVR).

What happened to Tanen’s stock options in the merger?

227,100 options became fully vested; in-the-money portions were cashed out, while options with strike ≥ $0.57 were cancelled for no value.

Does David M. Tanen hold any KRON securities after the transaction?

No. The Form 4 shows zero shares and zero options remaining after the merger settlement.

Why was this Form 4 necessary if Kronos Bio merged with Concentra?

Section 16 requires insiders to report final changes; this filing documents the termination of beneficial ownership and satisfies the last reporting obligation.