Welcome to our dedicated page for Kronos Bio SEC filings (Ticker: KRON), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
The Kronos Bio, Inc. (KRON) SEC filings archive documents the company’s history as a publicly traded biopharmaceutical and clinical-stage company focused on small molecule therapeutics targeting deregulated transcription in cancer and autoimmune diseases, and its subsequent transition to a wholly owned subsidiary of Concentra Biosciences, LLC. These filings provide primary-source detail on corporate transactions, listing status, and reporting obligations.
A Form 8-K dated June 20, 2025, describes the completion of a tender offer and merger pursuant to an Agreement and Plan of Merger with Concentra Biosciences, LLC and a Concentra merger subsidiary. The filing explains that the merger subsidiary completed a tender offer for all outstanding shares of Kronos Bio common stock for a cash amount per share plus a non-transferable contingent value right, and that, following the offer, the merger subsidiary merged with and into Kronos Bio. As a result, Kronos Bio continued as the surviving corporation and became a wholly owned subsidiary of Concentra, with a change in control of the registrant.
The same Form 8-K reports that Kronos Bio notified The Nasdaq Global Select Market of the merger’s consummation and requested suspension of trading in its common stock and the filing of a Form 25 to delist the shares and deregister them under Section 12(b) of the Securities Exchange Act of 1934. A Form 25 filed on June 20, 2025, by Nasdaq Stock Market LLC identifies Kronos Bio, Inc. and its common stock as the class of securities removed from listing and/or registration on Nasdaq.
Following the delisting, a Form 15 filed on June 30, 2025, by Kronos Bio, Inc. certifies the termination of registration of its common stock under Section 12(g) of the Exchange Act and the suspension of reporting obligations under Sections 13 and 15(d). The Form 15 indicates that there was one holder of record as of the certification date and cites Rule 12g-4(a)(1) and Rule 12h-3(b)(1)(i) as the provisions relied upon.
Together, these filings show the full sequence of regulatory steps: completion of the acquisition by Concentra, the resulting change in control, the request for Nasdaq delisting, the formal removal from listing via Form 25, and the termination of registration and reporting obligations via Form 15. Earlier periodic reports and other filings, which are referenced in company news releases discussing financial results and risk factors, provide additional context on Kronos Bio’s operations, pipeline, and financial position during its time as a public company.
On Stock Titan’s filings page for KRON, users can access these SEC documents and use AI-powered tools to interpret key sections. The Form 8-K offers detailed information on the merger terms, tender offer results, and post-merger governance changes. The Form 25 and Form 15 clarify the status of the common stock and the end of Exchange Act reporting. For anyone researching KRON as a historical ticker, these filings collectively explain how Kronos Bio transitioned from a Nasdaq-listed issuer to a privately held subsidiary.
Kronos Bio (NASDAQ: KRON) has received a Notice of Effectiveness from the SEC on June 23, 2025 for their POS AM (Post-Effective Amendment) filing. The amendment relates to Registration Statement File Number 333-283072.
A Post-Effective Amendment becomes effective when the SEC issues a notice of effectiveness, allowing the company to proceed with the amended registration statement. This filing indicates that Kronos Bio's previously filed registration statement modifications have been reviewed and approved by the SEC.
This administrative filing is a routine regulatory matter that confirms the effectiveness of Kronos Bio's amended registration statement, which may relate to securities offerings, equity compensation plans, or other registered securities.
Kronos Bio, Inc. (NASDAQ: KRON) filed five Post-Effective Amendments to previously effective Form S-8 registration statements in order to deregister all unsold shares that had been reserved for issuance under the company’s 2017 Equity Incentive Plan, 2020 Equity Incentive Plan, and 2020 Employee Stock Purchase Plan.
The administrative action follows the closing of the June 20, 2025 merger in which Concentra Merger Sub IV, Inc., a wholly-owned subsidiary of Concentra Biosciences, LLC, merged with and into Kronos Bio. Each outstanding common share was converted into the right to receive $0.57 in cash plus one non-transferable contingent value right (CVR). As Kronos now operates as a wholly-owned subsidiary of Concentra, all public offerings under the referenced S-8 statements have been terminated in accordance with prior undertakings, and the effectiveness of the statements has been withdrawn.
The filing is purely procedural: it eliminates the registration of roughly 34 million shares that remained unissued across the five plans, confirms that no additional equity will be issued, and finalises the company’s transition away from public-company status.
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.
Kronos Bio, Inc. (NASDAQ: KRON) filed five Post-Effective Amendment No. 1 filings to previously effective Form S-8 registration statements on 20 June 2025. The purpose is to deregister all unsold shares that had been reserved for issuance under the 2017 Equity Incentive Plan, the 2020 Equity Incentive Plan and the 2020 Employee Stock Purchase Plan.
The amendments follow the closing of the cash acquisition by Concentra Biosciences, LLC. Under the 1 May 2025 Agreement and Plan of Merger, completed on 20 June 2025, each outstanding Kronos share was converted into the right to receive $0.57 in cash plus one non-transferable contingent value right (CVR). With the merger consummated, Kronos has terminated all public offerings of its securities and is removing from registration every share that remains unissued under the five S-8 statements (originally covering millions of shares across the three plans).
As required by Rule 478 and the undertakings in each S-8, the filing formally ends the effectiveness of the registration statements, eliminating ongoing Exchange Act compliance obligations tied to those employee equity programs. The document is signed solely by Chief Financial Officer Michael Hearne pursuant to Securities Act Rule 478, reflecting Kronos’ new status as a wholly owned subsidiary and its exit from the public markets.