Plum Acquisition Corp. III: Marcum LLP Resigns as Auditor

What Happened

• Plum Acquisition Corp. III filed an 8-K on August 14, 2026 disclosing that Marcum LLP resigned as the company’s independent registered public accounting firm effective June 3, 2026. Marcum had continued to serve through that date after CBIZ CPAs P.C. acquired Marcum’s attest business effective November 1, 2024. The company provided Marcum a copy of this filing and requested a confirming letter; Marcum’s letter dated August 14, 2026 is filed as Exhibit 16.1.

Key Details

• Marcum resigned as auditor on June 3, 2026; CBIZ CPAs acquired Marcum’s attest business on November 1, 2024.
• For the years ended December 31, 2025 and 2024, and through June 3, 2026, the company did not consult Marcum or CBIZ CPAs on accounting application or audit-opinion matters, and there were no disagreements or reportable events, except as noted below.
• The reports of Marcum on the company’s consolidated financial statements for 2025 and 2024 were unqualified (no adverse opinion or disclaimer and no modifications).
• The only disclosed issue was a previously reported material weakness in the company’s internal control over financial reporting (disclosed in the 2025 Form 10‑K, Part II, Item 9A, and the 2026 Q1 Form 10‑Q, Part I, Item 4).

Why It Matters

• A change or resignation of the independent auditor is a material corporate event that investors monitor because it can affect audit continuity and confidence in financial reporting. In this case, Marcum’s reports for 2024 and 2025 were unqualified and the company reported no disagreements with Marcum, which reduces immediate red flags.
• Investors should note the previously disclosed material weakness in internal control and watch upcoming filings for any new auditor engagement letters, updated audit reports, or remediation steps addressing the control weakness.