Change in Certifying Accountants (Form 8-K)

Item 4.01. Changes in Registrant's Certifying Accountant.

Based on information provided by Marcum LLP ("Marcum"), the independent registered public accounting firm of Plum Acquisition Corp. III (the "Company"), CBIZ CPAs P.C. ("CBIZ CPAs") acquired the attest business of Marcum, effective November 1, 2024. Marcum continued to serve as the Company's independent registered public accounting firm through June 3, 2026. On June 3, 2026, Marcum resigned as the Company's independent registered public accounting firm.

During the years ended December 31, 2025 and 2024, and through June 3, 2026, the Company did not consult with Marcum or CBIZ CPAs regarding (i) the application of accounting principles to a specified transaction, either completed or proposed, or the type of audit opinion that might be rendered on the Company's consolidated financial statements, or (ii) any matter that was either the subject of a disagreement (as described in Item 304(a)(1)(iv) of Regulation S-K) or a reportable event (as described in Item 304(a)(1)(v) of Regulation S-K), except for the disclosure of the material weakness in the Company's internal control over financial reporting as disclosed in Part II, Item 9A of the Company's Annual Report on Form 10-K for the year ended December 31, 2025, and Part I, Item 4 of the Company's Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2026.

The reports of Marcum regarding the Company's consolidated financial statements for the fiscal years ended December 31, 2025 and 2024, did not contain any adverse opinion or disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope, or accounting principles.

During the years ended December 31, 2025 and 2024, and through June 3, 2026, the date of Marcum's resignation, there were (a) no disagreements (as defined in Item 304(a)(1)(iv) of Regulation S-K) between the Company and Marcum on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedures, which disagreements, if not resolved to the satisfaction of Marcum, would have caused Marcum to make reference to such disagreement in its reports and (b) no "reportable events" (as defined in Item 304(a)(1)(v) of Regulation S-K), except as disclosed above.

The Company provided Marcum with a copy of this Current Report on Form 8-K prior to its filing with the U.S. Securities and Exchange Commission (the "SEC") and requested that Marcum furnish the Company with a letter addressed to the SEC, pursuant to Item 304(a)(3) of Regulation S-K, stating whether it agrees with the above statements and, if it does not agree, the respects in which it does not agree. A copy of the letter, dated August 14, 2026, is filed as Exhibit 16.1 to this Current Report on Form 8-K and incorporated herein by reference.