MBX Biosciences (MBX) Proxy filing summary

Executive summary

• The 2026 Annual Meeting will be held virtually on June 4, 2026, with shareholders able to vote and submit questions online.

• Shareholders will vote on electing two Class II directors and ratifying Ernst & Young LLP as the independent auditor for 2026.

• Only shareholders of record as of April 10, 2026, are entitled to vote; 47,570,485 shares are outstanding and eligible.

• The company uses a Notice and Access model for proxy materials, reducing costs and environmental impact.

Voting matters and shareholder proposals

• Proposal 1: Election of Patrick J. Heron and Edward T. Mathers as Class II directors for a three-year term ending in 2029.

• Proposal 2: Ratification of Ernst & Young LLP as independent registered public accounting firm for fiscal year ending December 31, 2026.

• Shareholders may submit proposals for the 2027 meeting by December 23, 2026, and must comply with SEC and bylaw requirements.

• Voting is available by internet, phone, mail, or during the virtual meeting; no cumulative voting rights.

Board of directors and corporate governance

• The board is divided into three staggered classes; majority are independent directors except the CEO.

• Four standing committees: Audit, Compensation, Nominating and Corporate Governance, and Science and Medicine.

• Each committee has defined charters and meets regularly; all committee members meet independence and financial literacy standards.

• Board and committee attendance exceeded 75% in 2025; directors are expected to attend annual meetings.

• Insider trading and code of ethics policies are in place; policies prohibit short sales and derivative transactions without approval.