Merger Agreement

On July 28, 2026, the Company entered into an Agreement and Plan of Merger (the Merger Agreement) by and among the Company, Caldera, Parent, Yellowstone Merger Sub, Inc., a Delaware corporation and a direct, wholly owned subsidiary of Parent (Caldera Merger Sub), and Sonic Merger Sub, Inc., a Delaware corporation and a direct, wholly owned subsidiary of Parent (Synlogic Merger Sub).

Pursuant to the Merger Agreement, and upon the terms and subject to the satisfaction of the conditions described therein, Synlogic will be merged with and into Synlogic Merger Sub, with Synlogic surviving as a wholly owned subsidiary of Parent, and Caldera will be merged with and into Caldera Merger Sub, with Caldera surviving as a wholly owned subsidiary of Parent (together, the Caldera Mergers). The Caldera Mergers are intended to qualify as a tax-free reorganization for U.S. federal income tax purposes.

Concurrently with entering into the Merger Agreement, Caldera entered into a securities purchase agreement (the Securities Purchase Agreement) with certain qualified institutional buyers and/or accredited investors (the Investors). Pursuant to the Securities Purchase Agreement, and subject to the terms and conditions therein, Caldera agreed to sell, and the Investors agreed to purchase, an aggregate of approximately $278.0 million worth of shares of Caldera Common Stock (the Concurrent Financing). The closing of the Concurrent Financing is anticipated to occur on or about the date of the closing of the Caldera Mergers, subject to the satisfaction of customary closing conditions.

Assuming that the Caldera Mergers close, on a pro forma basis, pre-merger equityholders of the Company are expected to own approximately 2.3% of the combined company, pre-merger equityholders of Caldera are expected to own approximately 62.8% of the combined company, and the Investors are expected to own approximately 34.9% (assuming proceeds from the financing of $278.0 million), in each case, calculated on a fully diluted basis, using the treasury stock method, and subject to certain assumptions, including (i) a valuation for the Company of $18.0 million, assuming the Company has net cash of $6.0 million as of the closing of the Caldera Mergers, (ii) a valuation for Caldera of $500.0 million, and (iii) the relative capitalization of the Company and Caldera. The percentage of the combined company that each party’s equity holders will own following the Closing is subject to certain adjustments as described in the Merger Agreement, including the amount of the Final Synlogic Net Cash at Closing (as defined in the Merger Agreement).

In connection with the Caldera Mergers, Parent will prepare and file a registration statement on Form S-4, which will contain a prospectus to register the shares of Parent Common Stock issued pursuant to the Merger Agreement (the Form S-4). Promptly after the Form S-4 is declared effective, the Company shall hold a stockholder meeting to seek the vote of the Company’s stockholders of, among other matters, the approval of the Merger Agreement and the transactions contemplated therein. The Caldera Mergers will close after approval by the stockholders of the Company and Caldera, the S-4 becomes effective, and certain other conditions, as specified in the Merger Agreement, are satisfied.

Warrant Agreements

In October 2023, in an underwritten public offering, Synlogic issued to certain purchasers (the Holders) common warrants (the Warrants) to purchase up to an aggregate of 7,394,363 shares of Synlogic Common Stock (the Warrant Shares) exercisable at $3.408 per share, subject to adjustment (the Exercise Price). On July 27, 2026, Synlogic entered into warrant amending agreements (collectively, the Warrant Amending Agreements) with all the Holders that (i) reduced the Exercise Price of the Warrants to $0.70 per Warrant Share and (ii) removed the Holders’ right to require Synlogic or a successor entity to redeem the Warrants for cash in an amount equal to the Black-Scholes value of the unexercised portion thereof, concurrently with or within 30 days following the consummation of a fundamental transaction.