[S-8 POS] Kronos Bio, Inc. SEC Filing

Rhea-AI Filing Summary

On 20 June 2025, Kronos Bio, Inc. (KRON) submitted five Post-Effective Amendment No. 1 filings to its prior Form S-8 registration statements, formally deregistering all remaining unissued shares tied to the company’s employee equity plans. The amendments cover the 2017 Equity Incentive Plan, the 2020 Equity Incentive Plan and the 2020 Employee Stock Purchase Plan, which together had originally registered more than 17 million shares across filings 333-249424, 333-254620, 333-262993, 333-270564 and 333-278125.

The clean-up filing follows the completion of the previously announced merger with Concentra Biosciences. Effective the same day, Concentra Merger Sub IV merged into Kronos, leaving Kronos as a wholly owned subsidiary. Each outstanding KRON common share—except those held in treasury, by the buyer or by dissenting holders—was converted into the right to receive $0.57 in cash plus one non-transferable contingent value right (CVR).

Because the merger terminates any future issuances under the equity plans, Kronos has ended the related securities offerings and removed any unsold securities from registration, satisfying its undertaking under Rule 415. The filing is largely administrative, eliminates potential dilution from unused plan shares and confirms that KRON equity no longer trades publicly.

Positive

• Completion of the merger provided shareholders with $0.57 cash per share plus a contingent value right.
• Deregistration of all unsold equity plan shares eliminates any future dilution risk.

Negative

• KRON is now a privately held subsidiary; public investors no longer have direct access to the company’s equity.

Insights

M&A Specialist

TL;DR: Housekeeping S-8 POS removes unused plan shares after close of $0.57-per-share takeover; no incremental valuation impact.

All substantive economics of the Concentra transaction were set when the merger agreement was signed on 1 May 2025. Today’s filing merely perfects post-closing mechanics: it terminates the five equity-plan registration statements and deregisters roughly 17 million shares that would otherwise remain on the SEC’s books. By extinguishing any residual issuance authority, the parent eliminates hypothetical dilution and tidies up compliance exposure. Investors already received their cash and CVR; therefore, the amendment does not change consideration or introduce new liabilities. Materiality is minimal and purely procedural.

Securities Analyst

TL;DR: Filing finalises KRON’s exit from capital markets; equity plans void, shares deregistered, impact neutral for former public holders.

From a securities-law perspective, filings under Rule 478 allow one officer—here the CFO—to sign amendments that terminate the effectiveness of the S-8s. Kronos’ designation as a non-accelerated, smaller reporting company remains irrelevant going forward because it will cease periodic reporting. The CVR structure means upside, if any, lies outside KRON’s former equity; today’s action only confirms no further plan-share supply can hit the market. Consequently the news is operationally neutral and investment-grade portfolios that still carry KRON tickers should already have been redeemed at $0.57. Impact classification: not impactful.

As filed with the Securities and Exchange Commission on June 20, 2025

Registration No. 333-278125

Registration No. 333-270564

Registration No. 333-262993

Registration No. 333-254620

Registration No. 333-249424

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-278125

POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-270564

POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-262993

POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-254620

POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT NO. 333-249424

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

KRONOS BIO, INC.

(Exact name of registrant as specified in its charter)

Delaware		82-1895605
(State or other jurisdiction of incorporation or organization)		(IRS employer identification number)

301 Binney Street, 2nd Floor East

Cambridge, MA 02142

(Address of Principal Executive Offices, including Zip Code)

2017 Equity Incentive Plan (Prior Plan)

2020 Equity Incentive Plan

2020 Employee Stock Purchase Plan

(Full title of the Plans)

Michael Hearne

Chief Financial Officer

Kronos Bio Inc.

4747 Executive Drive, Suite 210

San Diego, California 92121

(858) 281-5372

(Name, Address and Telephone Number, including Area Code, of Agent for Service)

Copies to:

Ryan A. Murr

Gibson, Dunn & Crutcher LLP

One Embarcadero Center Suite 2600

San Francisco, California 94111

(415) 393-8200

Michael R. Patrone, Esq.

Amanda J. Gill, Esq.

Goodwin Procter LLP

New York Times Bldg

620 8th Ave

New York, NY 10018

(212) 813-8800

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See definitions of “large accelerated filer, “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer	☐	Accelerated filer	☐
Non-accelerated filer	☒	Smaller reporting company	☒
		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 7(a)(2)(B) of the Securities Act.  ☐

EXPLANATORY NOTE

DEREGISTRATION OF UNSOLD SECURITIES

These Post-Effective Amendments (the “Post-Effective Amendments”) filed by Kronos Bio, Inc., a Delaware corporation (the “Registrant”), to deregister all shares of the Registrant’s common stock, $0.001 par value per share (the “Shares”), remaining unissued under the following Registration Statements on Form S-8 (each, a “Registration Statement”, and collectively, the “Registration Statements”) filed by the Registrant with the U.S. Securities and Exchange Commission (the “Commission”).

• Registration Statement on Form S-8 (No. 333-249424) pertaining to the registration of (i) 3,433,122 Shares issuable under the 2017 Equity Incentive Plan (the “2017 Plan”), (ii) 12,075,323 Shares issuable under the 2020 Equity Incentive Plan (the “2020 Plan”) and (iii) 688,000 Shares issuable under the 2020 Employee Stock Purchase Plan (the “ESPP”).

• Registration Statement on Form S-8 (No. 333-254620) pertaining to the registration of (i) 2,801,675 Shares issuable under the 2020 Plan and (ii) 560,335 Shares issuable under the ESPP.

• Registration Statement on Form S-8 (No. 333-262993) pertaining to the registration of (i) 2,828,994 Shares issuable under the 2020 Plan and (ii) 565,798 Shares issuable under the ESPP.

• Registration Statement on Form S-8 (No. 333-270564) pertaining to the registration of (i) 2,848,371 Shares issuable under the 2020 Plan and (ii) 569,674 Shares issuable under the ESPP.

• Registration Statement on Form S-8 (No. 333-278125) pertaining to the registration of (i) 2,947,329 Shares issuable under the 2020 Plan and (ii) 589,465 Shares issuable under the ESPP.

The Registrant is filing these Post-Effective Amendments to withdraw and remove any unissued and unsold securities issuable by Registration pursuant to the above-referenced Registration Statements.

On May 1, 2025, the Registrant entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Concentra Biosciences, LLC, a Delaware limited liability company (“Parent”), and Concentra Merger Sub IV, Inc., a Delaware corporation and wholly owned subsidiary of Parent (“Merger Sub”). Pursuant to the Merger Agreement, on June 20, 2025, Merger Sub was merged with and into the Registrant with the Registrant surviving as a wholly owned subsidiary of Parent (the “Merger”). In the Merger, each share of Common Stock (the “Shares”) (other than (i) Shares owned or held in the Company’s treasury immediately prior to the Effective Time, (ii) Shares owned directly or indirectly by Parent or Merger Sub immediately prior to the Effective Time and (iii) Shares held by any stockholder of the Registrant who properly exercised appraisal rights under Delaware law) was converted into the right to receive $0.57 in cash per Share, plus one non-transferrable contractual contingent value right for each Share.

As a result of the Merger, the Registrant has terminated all offerings of its securities pursuant to the Registration Statements. In accordance with an undertaking made by the Registrant in each of the Registration Statements to remove from registration, by means of a post-effective amendment, any of the securities that had been registered for issuance that remain unsold at the termination of the offerings, the Registrant hereby removes from registration all such securities registered under the Registration Statements that remain unsold as of the date hereof and terminates the effectiveness of the Registration Statements.

SIGNATURE

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused these Post-Effective Amendments to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of San Diego, State of California, on June 20, 2025. No other person is required to sign these Post-Effective Amendment to the Registration Statements in reliance on Rule 478 of the Securities Act of 1933, as amended.

KRONOS BIO, INC.

/s/ Michael Hearne

Name: Michael Hearne

Title: Chief Financial Officer

FAQ

How much did Kronos Bio (KRON) shareholders receive in the Concentra Biosciences merger?

Each share was converted into $0.57 in cash plus one non-transferable contingent value right.

Why did Kronos Bio file Post-Effective Amendments to its Form S-8 registrations?

The company terminated all securities offerings after the merger and is removing any unsold shares from registration.

Which equity plans were affected by the deregistration?

The 2017 Equity Incentive Plan, the 2020 Equity Incentive Plan and the 2020 Employee Stock Purchase Plan.

Approximately how many shares were originally registered across the five Form S-8 filings?

The filings collectively covered about 17 million shares (common stock) for potential issuance.

Is Kronos Bio still required to file SEC reports after this amendment?

No. As a wholly owned subsidiary of Concentra Biosciences, Kronos Bio will cease public company reporting obligations.