MBX Biosciences Announces Closing of Upsized Initial Public Offering, Including Full Exercise of Underwriters’ Option to Purchase Additional Shares Page 1

CARMEL, Ind., Sept. 16, 2024 (GLOBE NEWSWIRE) — MBX Biosciences, Inc. (Nasdaq: MBX) (“MBX Biosciences”), a clinical-stage biopharmaceutical company focused on the discovery and development of novel precision peptide therapeutics for the treatment of endocrine and metabolic disorders, today announced the closing of its previously announced increased initial public offering of 11,730,000 shares of its common stock at a price to the public of $16.00 per share, including 1,530,000 shares issuable upon the exercise in full by the underwriters of their option to purchase additional shares of common stock in the offering. The aggregate gross proceeds to MBX Biosciences from the offering were approximately $187.7 million, before deducting underwriting discounts and commissions and offering expenses.

The shares began trading on the Nasdaq Global Select Market under the ticker symbol “MBX” on September 13, 2024.