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.
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.
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.
Form 4 filing overview for Kronos Bio, Inc. (KRON)
The filing details the disposition of four tranches of stock options held by director Roshawn A. Blunt on 20 June 2025. The options, with exercise prices of $17.10, $3.53, $1.48 and $0.95, were cancelled or exchanged in connection with the closing of Kronos Bio’s merger with Concentra Biosciences LLC.
- Merger consideration for common shareholders: $0.57 per share in cash plus one contingent value right (CVR).
- Pursuant to the merger agreement, all unexercised options became fully vested immediately prior to the effective time.
- If an option’s exercise price was higher than the $0.57 cash amount, it was cancelled for no consideration; otherwise, the holder received the cash spread plus one CVR per underlying share.
- All four option grants had exercise prices above $0.57, resulting in no economic value to the reporting person. Post-transaction, Blunt reports zero derivative securities beneficially owned.
- The tender offer and subsequent merger were completed on 18 June 2025; the Form 4 documents changes dated 20 June 2025.
Because the merger converts Kronos Bio into a wholly-owned subsidiary of Concentra, this filing also serves as notice that the director is no longer subject to Section 16 reporting.
Kronos Bio, Inc. (KRON) – Form 4 insider transaction
Director Joshua A. Kazam reported the disposition of his entire equity position in connection with the closing of Kronos Bio’s merger with Concentra Biosciences (effective 20 June 2025).
- Common shares: 94,481 shares tendered at $0.57 per share + one contingent value right (CVR), the consideration outlined in the May 1, 2025 merger agreement.
- Stock options: 123,600 options with strike prices ranging from $0.95-$24.18 were cancelled/disposed; all strikes exceeded the $0.57 cash offer, so they were out-of-the-money and received no cash but one CVR per underlying share.
- Following the transactions, the reporting person shows zero direct or indirect ownership in KRON.
The filing confirms the tender-offer closing and subsequent merger that takes Kronos Bio private as a wholly owned subsidiary of Concentra Biosciences. Public shareholders have already received the same $0.57 + CVR consideration. Trading in KRON is expected to cease once post-merger formalities finish.