C5 Acquisition Corporation entered into a material definitive agreement for the private placement of non-interest bearing, unsecured promissory note for gross proceeds of up to $320,000 on April 11, 2023. The transaction will include participation from returning lenderr, C5 Sponsor LLC. At the election of the C5 Sponsor LLC, up to $2,000,000 of the principal amount of this note may be converted into private placement warrants of the company, with such terms as are described in the prospectus included in the registration statement on Form S-1 (Reg.

No. 333-261249) filed by the company with the Securities and Exchange Commission and declared effective on January 6, 2022, at a price of $1.00 per warrant. Each contribution will be paid monthly beginning on May 11, 2023 and thereafter on the eleventh day of each month (or if such eleventh day is not a business day, on the business day immediately preceding such eleventh day) until the earliest to occur of (i) the consummation of the business combination, (ii) December 11, 2023 and (iii) if a business combination is not consummated, the date of liquidation of the trust account, as determined in the sole discretion of the company?s board of directors.

The promissory note will mature on the earlier of the date the company consummates a business combination or the date that the winding up of the company is effective. The promissory note will not bear any interest, and will be repayable by the company to the sponsor upon the maturity date.