3. Discontinued Operations and TSA

On September 30, 2024, the Company completed the sale (the “Transaction”) of its VOWST microbiome therapeutic business (the “VOWST Business”), including inventory and equipment, certain patents and patent applications, know-how, trade secrets, trademarks, domain names, marketing authorizations and related rights, documents, materials, business records and data and contracts that are used or held for use primarily in the development, commercialization and manufacturing of the microbiome product sold under the brand name VOWST as provided for in accordance with the terms of the Purchase Agreement (the “Product”), to Société des Produits Nestlé S.A. (“SPN”), a wholly-owned subsidiary of Nestlé S.A., and its designated affiliates (collectively, “Nestlé Health Science”) pursuant to the Asset Purchase Agreement, dated as of August 5, 2024 (the “Purchase Agreement”), by and among the Company and SPN, and a wholly-owned subsidiary of Nestlé S.A.

The Company also entered into a Transition Services Agreement (“TSA”) with Nestlé Enterprises S.A., (“NESA”), an affiliate of SPN, in connection with the Transaction, through which the Company provided certain manufacturing services until December 31, 2025, and other transition services, for the duration specified in the schedule to the TSA for each service. The Company's obligations under the TSA are now complete. For the three and six months ended June 30, 2026 and 2025, the Company recognized $0, $0, $3,490, and $9,799 respectively, of TSA reimbursement income in other income in the Company’s condensed consolidated statements of operations and comprehensive (loss) income. For the three and six months ended June 30, 2026 and 2025, the Company incurred $0, $0, $1,689, and $5,216, respectively, of expenses related to manufacturing services and $0, $0, $1,261, and $3,509, respectively, of TSA labor and passthrough expenses to support the transition services, including finance and accounting, information technology, human resources, operations, and other services.

For the three and six months ended June 30, 2026 and 2025, $0, $0, $4,585, and $11,987, respectively, was billed to NESA related to transition services performed by the Company, and the Company received $0, $360, $6,464, and $63,173 from NESA during the periods, respectively. The payments received in the first quarter of 2025 included the installment payment of $50,000 received in January 2025 which was conditioned on the Company’s material compliance with obligations under the TSA. The installment payment was recognized in Gain on sale of VOWST Business within continuing operations in the Company’s condensed consolidated statements of operations and comprehensive income for the six months ended June 30, 2025 as the gain was realizable.

The Company has estimated costs associated with certain accrued liabilities due to SPN - related party as a loss contingency in accordance with ASC 450, Contingencies. These contingent liabilities are presented as Accrued Liabilities due to SPN - related

The contingent liabilities accrued on the Company's condensed consolidated balance sheet are remeasured at each reporting period based on i) cash payments made by the Company to reduce the accrued liabilities due to SPN - related party and ii) revised estimates of the total remaining liabilities due to SPN - related party. For the three and six months ended June 30, 2026 and 2025, the Company recognized a gain on sale of VOWST Business of $0, $0, $185, and $2,366, respectively, as a result of the change in accrued liabilities due to SPN - related party.

On June 2, 2026, the Company entered into Amendment No. 1 (the “APA Amendment”) to the Purchase Agreement. Pursuant to the Purchase Agreement, SPN agreed to pay the Company certain one-time contingent milestone payments during the Milestone Period (as defined in the Purchase Agreement) if and following the first time that the worldwide annual net sales of the Product (as defined in the Purchase Agreement) reached the following thresholds: (i) a $125,000 milestone payment upon the first calendar year in which annual worldwide net sales of the Product equal or exceed $400,000 (the “Second Sales Milestone Payment”); and (ii) a $150,000 milestone payment upon the first calendar year in which annual worldwide net sales of the Product equal or exceed $750,000 (the “Third Sales Milestone Payment”). Pursuant to the Purchase Agreement, the Prepaid Milestone (as defined in the Purchase Agreement) accrued interest during the Milestone Period, which would reduce the Second Milestone Payment to Seres if and when it became payable (the “Milestone Interest Payments”). Pursuant to the APA Amendment, the parties agreed to terminate SPN’s obligations with respect to the Second Sales Milestone Payment, the Third Sales Milestone Payment and eliminate the Milestone Interest Payments that would have been due from the Company to SPN. In consideration for the foregoing, SPN agreed to a one-time payment to the Company of $25,000 (the “Milestone Termination Payment”), which amount is payable in two equal installments of $12,500, with the first installment paid on July 1, 2026 and the second installment payable on October 1, 2026.

As there are no conditions under which the Company would be required to repay the $25,000, or any portion of the interest that was accruing on the Prepaid Milestone under the Purchase Agreement, and there are no circumstances under which SPN would be relieved of its obligation to make this payment to the Company, the gain is considered realizable in June 2026 when the APA Amendment was signed. The Company recorded a Gain on Sale of VOWST Business within continuing operations of $25,000 during the three months ended June 30, 2026 because the amount is fixed consideration and is no longer contingent on a future event. As of June 30, 2026 and December 31, 2025, the Company had $25,000 and $360 in accounts receivable due from SPN - related party in the Company’s condensed consolidated balance sheets.