Boundless Bio Announces Merger Agreement to Acquire Serapha Bio

What Happened

• Boundless Bio, Inc. announced it and its wholly owned subsidiary Boulder Merger Sub Corp. entered into an Agreement and Plan of Merger and Reorganization with Serapha Bio, Inc., under which Merger Sub will merge into Serapha and Serapha will become a wholly owned subsidiary of Boundless Bio. The original agreement was entered June 22, 2026; Amendment No. 1 to the Merger Agreement was filed as Exhibit 2.1 on August 28, 2026.
• The company said it will file a Form S-4 containing the proxy statement and prospectus for the transaction and noted that the merger closing is subject to customary conditions, potential adjustments to the exchange ratio and a Company Pre‑Closing Financing.

Key Details

• Parties: Boundless Bio, Boulder Merger Sub Corp. (wholly owned by Boundless) and Serapha Bio.
• Dates: Original Merger Agreement — June 22, 2026; Amendment No. 1 filed — August 28, 2026.
• Filings: Amendment No. 1 is included as Exhibit 2.1; Boundless Bio will file a Form S-4 (proxy statement and prospectus) with the SEC.
• Noted contingencies/risks disclosed: closing conditions, timing uncertainty, potential adjustments to the exchange ratio and cash dividend, need for pre‑closing financing, and Serapha’s reliance on an IP license from YolTech Therapeutics.

Why It Matters

• This is a material corporate transaction that would make Serapha a wholly owned subsidiary of Boundless Bio and could change ownership percentages and the company’s capital structure once completed. Investors should watch for the Form S-4/proxy for transaction economics, the outcome of the pre‑closing financing, any adjustments to the exchange ratio or dividend, and the timing/conditions required for closing. The 8‑K also highlights specific risks (financing, regulatory/closing conditions, IP reliance) that could affect the deal’s completion.