--- schema_version: "secwatch.filing_event.v1" accession: "0001193125-23-259403" form_type: "8-K" ticker: null cik: "0001827506" company_name: "Tourmaline Bio, Inc." filed_at: "2023-10-20T23:59:59+00:00" generated_at: "2026-06-09T18:52:26.039507+00:00" event_type: "m_and_a" sentiment: "neutral" materiality_score: 0.95 calibrated_materiality_score: 0.95 confidence: "high" source: SEC EDGAR --- # Tourmaline Bio completes reverse merger with Talaris; 78.1% ownership to former Tourmaline holders ## Summary - Merger closed Oct. 19, 2023; Tourmaline survived as wholly owned sub, renamed Tourmaline Bio, Inc. - Reverse stock split 1-for-10 effected at 4:00 p.m. ET; new CUSIP 89157D 105. - Former Tourmaline stockholders receive ~15.9M shares (0.7977 exchange ratio, pre-split); own 78.1% of post-merger company. - New board of 7 directors: 2 from legacy Talaris, 5 from Tourmaline; Sandeep Kulkarni named CEO. - Common stock trades on Nasdaq under new ticker TRML starting Oct. 20, 2023. ## SEC filing metadata - accession: 0001193125-23-259403 - form_type: 8-K - cik: 0001827506 - company_name: Tourmaline Bio, Inc. - filed_at: 2023-10-20T23:59:59+00:00 - event_type: m_and_a - sentiment: neutral - materiality_score: 0.95 - calibrated_materiality_score: 0.95 - confidence: high - sec_items: 2.01, 1.01, 5.02, 3.03, 5.01, 5.03, 8.01, 9.01 - EDGAR index: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/d571384d8k.htm ## Machine-readable alternates - HTML: https://secwatch.observer/filing/0001193125-23-259403 - JSON: https://secwatch.observer/filing/0001193125-23-259403.json - Plain text: https://secwatch.observer/filing/0001193125-23-259403.txt ## Key facts - Executive change Geoff MacKay resigned as Director at Tourmaline Bio, Inc.. - Action: resigned - Role: Director source text: Sandip Agarwala, Suzanne T. Ildstad, M.D., Geoff MacKay, Francois Nader, M.D., Gaurav D. Shah, M.D. and Karen L. Smith, M.D. resigned from the Company’s board of directors and committees of the board of directors on which they respectively served, which resignations were not the result of any disagreements with the Company relating to the Company’s operations, policies or practices. evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Gaurav D. Shah, M.D. resigned as Director at Tourmaline Bio, Inc.. - Action: resigned - Role: Director source text: Sandip Agarwala, Suzanne T. Ildstad, M.D., Geoff MacKay, Francois Nader, M.D., Gaurav D. Shah, M.D. and Karen L. Smith, M.D. resigned from the Company’s board of directors and committees of the board of directors on which they respectively served, which resignations were not the result of any disagreements with the Company relating to the Company’s operations, policies or practices. evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Cariad Chester was appointed as Director at Tourmaline Bio, Inc.. - Action: appointed - Role: Director source text: Cariad Chester and Sapna Srivastava appointed as Class III directors evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Parvinder Thiara was appointed as Director at Tourmaline Bio, Inc.. - Action: appointed - Role: Director source text: Sandeep Kulkarni, Mark McDade and Parvinder Thiara appointed as Class II directors evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Caley Castelein was appointed as Director at Tourmaline Bio, Inc.. - Action: appointed - Role: Director source text: Aaron Kantoff and Caley Castelein appointed as Class I directors evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Sandip Agarwala resigned as Director at Tourmaline Bio, Inc.. - Action: resigned - Role: Director source text: Sandip Agarwala, Suzanne T. Ildstad, M.D., Geoff MacKay, Francois Nader, M.D., Gaurav D. Shah, M.D. and Karen L. Smith, M.D. resigned from the Company’s board of directors and committees of the board of directors on which they respectively served, which resignations were not the result of any disagreements with the Company relating to the Company’s operations, policies or practices. evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Sapna Srivastava was appointed as Director at Tourmaline Bio, Inc.. - Action: appointed - Role: Director source text: Cariad Chester and Sapna Srivastava appointed as Class III directors evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Suzanne T. Ildstad, M.D. resigned as Director at Tourmaline Bio, Inc.. - Action: resigned - Role: Director source text: Sandip Agarwala, Suzanne T. Ildstad, M.D., Geoff MacKay, Francois Nader, M.D., Gaurav D. Shah, M.D. and Karen L. Smith, M.D. resigned from the Company’s board of directors and committees of the board of directors on which they respectively served, which resignations were not the result of any disagreements with the Company relating to the Company’s operations, policies or practices. evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Karen L. Smith, M.D. resigned as Director at Tourmaline Bio, Inc.. - Action: resigned - Role: Director source text: Sandip Agarwala, Suzanne T. Ildstad, M.D., Geoff MacKay, Francois Nader, M.D., Gaurav D. Shah, M.D. and Karen L. Smith, M.D. resigned from the Company’s board of directors and committees of the board of directors on which they respectively served, which resignations were not the result of any disagreements with the Company relating to the Company’s operations, policies or practices. evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Mark McDade was appointed as Director at Tourmaline Bio, Inc.. - Action: appointed - Role: Director source text: Sandeep Kulkarni, Mark McDade and Parvinder Thiara appointed as Class II directors evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Francois Nader, M.D. resigned as Director at Tourmaline Bio, Inc.. - Action: resigned - Role: Director source text: Sandip Agarwala, Suzanne T. Ildstad, M.D., Geoff MacKay, Francois Nader, M.D., Gaurav D. Shah, M.D. and Karen L. Smith, M.D. resigned from the Company’s board of directors and committees of the board of directors on which they respectively served, which resignations were not the result of any disagreements with the Company relating to the Company’s operations, policies or practices. evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Sandeep Kulkarni was appointed as Director at Tourmaline Bio, Inc.. - Action: appointed - Role: Director source text: Sandeep Kulkarni, Mark McDade and Parvinder Thiara appointed as Class II directors evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - Executive change Aaron Kantoff was appointed as Director at Tourmaline Bio, Inc.. - Action: appointed - Role: Director source text: Aaron Kantoff and Caley Castelein appointed as Class I directors evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - M&A Transactions Tourmaline Bio, Inc. underwent a change of control involving Tourmaline Bio, Inc. (formerly Tourmaline Sub, Inc.) for exchange ratio of 0.7977 shares of the Company’s common stock for each share of Tourmaline common stock (closed 2023-10-19). - Action: change of control - Counterparty: Tourmaline Bio, Inc. (formerly Tourmaline Sub, Inc.) - Consideration: exchange ratio of 0.7977 shares of the Company’s common stock for each share of Tourmaline common stock - Closing: 2023-10-19 source text: effective time of the Merger, the Company issued an aggregate of approximately 15,877,090 shares of its common stock to Tourmaline’s stockholders, based on an exchange ratio of 0.7977 (without giving effect to the Reverse Stock Split) shares of the Company’s common stock for each share of Tourmaline common stock outstanding immediately prior to the Merger, evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm - M&A Transactions Tourmaline Bio, Inc. completed an acquisition involving Tourmaline Bio, Inc. (as target) (closed 2023-10-19). - Action: acquisition - Counterparty: Tourmaline Bio, Inc. (as target) - Closing: 2023-10-19 source text: On October 19, 2023, the Company, Merger Sub and Tourmaline consummated the transactions contemplated by the Merger Agreement evidence_url: https://www.sec.gov/Archives/edgar/data/1827506/000119312523259403/0001193125-23-259403-index.htm This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.