Keystone Acquisition Corp.

We are a newly incorporated blank check company incorporated as a Cayman Islands exempted company and incorporated for the purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses or entities, which we refer to throughout this prospectus as our initial business combination. We have not selected any potential business combination target and we have not, nor has anyone on our behalf, initiated any substantive discussions, directly or indirectly, with any potential business combination target.

Current securities

1. 10-Q filingAug 13, 2026
2. Other EventsJun 18, 2026
3. Other EventsJun 10, 2026
4. Entry into a Material Definitive Agreement · Unregistered Sales of Equity Securities · Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements · Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year · Other EventsJun 8, 2026
5. 424B4 filingJun 3, 2026