0001527599 2026-03-31 0001527599 2025-01-01 2025-12-31 0001527599 2025-06-30 0001527599 2023-09-20 2025-01-01 2025-12-31 shares iso4217:USD 0001527599 FY true 10-K/A true 2025-12-31 --12-31 2025 false 001-37566 SYNLOGIC, INC. DE 26-1824804 PO Box 30 Winchester MA 01890 617 659-2802 No No Yes Yes Non-accelerated Filer true false false false true 4400000 11698919 DOCUMENTS INCORPORATED BY REFERENCENone. This registrant is filing this Amendment No. 1 (“Amendment”) to its Annual Report on Form 10-K for the year ended December 31, 2025 as filed with the Securities and Exchange Commission (the “SEC”) on March 12, 2026 (the “Original Filing”) solely to include the information required by Item 10 - “Directors, Executive Officers and Corporate Governance,” Item 11 - “Executive Compensation,” Item 12 - “Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters,” Item 13 - “Certain Relationships and Related Transactions, and Director Independence” and Item 14 - “Principal Accounting Fees and Services” of Part III of Form 10-K that was intentionally omitted from Part III of Original Filing. The reference on the cover page of the Original Filing to the incorporation by reference of portions of our definitive proxy statement into Part III of the Original Filing is hereby deleted. Items 10, 11, 12, 13 and 14 of Part III of the Original Filing are amended and restated in their entirety as set forth in this Amendment. In addition, pursuant to Rule 13a-14(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), we are including with this Amendment certain currently dated certifications. Because no financial statements have been included in this Amendment and this Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the certifications have been omitted. We are not including the certifications under Section 906 of the Sarbanes-Oxley Act of 2002 as no financial statements are being filed with this Amendment. Except as described above, no other amendments are being made to the Original Filing. This Amendment does not reflect events occurring after the March 12, 2026 filing of the Original Filing or modify or update the disclosure contained in the Original Filing in any way other than as required to reflect the amendments discussed above and reflected below. Accordingly, this Amendment should be read in conjunction with the Original Filing and our other filings with the SEC. Terms used but not defined herein shall have the meanings ascribed to them in the Original Filing. true On September 20, 2023, our Board adopted a Clawback Policy to comply with the new Clawback rules and listing standards promulgated by the SEC and Nasdaq Stock Market, respectively. The Clawback Policy generally provides that we will seek to recover, in the event of a required accounting restatement, excess incentive compensation received by covered officers where that compensation is based on erroneously reported financial information, regardless of fault or misconduct. 2023-09-20 KPMG LLP Boston, MA 185