Octave Specialty Group Inc. Reports Certifying Accountant Change

TL;DR

Octave Specialty Group (AMBC) changed its auditor, filing an 8-K on Dec 15, 2025.

AI Summary

Octave Specialty Group, Inc. filed an 8-K on December 15, 2025, reporting a change in its certifying accountant. The company, formerly known as Ambac Financial Group, Inc., has updated its principal executive offices to 40 Wall Street, New York, NY 10005.

Why It Matters

A change in a company's auditor can signal potential shifts in financial reporting or internal controls, warranting investor attention.

Risk Assessment

Risk Level: low — This filing is a routine administrative update regarding a change in the company's auditor and does not inherently indicate financial distress or significant operational changes.

Key Players & Entities

• Octave Specialty Group, Inc. (company) — Registrant
• Ambac Financial Group, Inc. (company) — Former Name
• December 10, 2025 (date) — Earliest event reported
• December 15, 2025 (date) — Date of report
• 40 Wall Street, New York, NY 10005 (address) — Principal executive offices

FAQ

Key Financial Figures

• $0.01 — ich registered Common stock, par value $0.01 per share OSG New York Stock Exchange

Filing Documents

• ambc-20251210.htm (8-K) — 46KB
• a04-0914q20258xkex161.htm (EX-16.1) — 4KB
• a04-0914q20258xkex991.htm (EX-99.1) — 6KB
• kpmglogo.jpg (GRAPHIC) — 5KB
• kpmgsignature.jpg (GRAPHIC) — 6KB
• 0001628280-25-057024.txt ( ) — 231KB
• ambc-20251210.xsd (EX-101.SCH) — 2KB
• ambc-20251210_def.xml (EX-101.DEF) — 16KB
• ambc-20251210_lab.xml (EX-101.LAB) — 28KB
• ambc-20251210_pre.xml (EX-101.PRE) — 17KB
• ambc-20251210_htm.xml (XML) — 4KB

01 Change in Registrant's Certifying Accountant

Item 4.01 Change in Registrant's Certifying Accountant (a) Dismissal of Previous Independent Registered Public Accounting Firm As a matter of good corporate governance, the Audit Committee of the Board of Directors (the "Audit Committee") of Octave Specialty Group, Inc., formerly known as Ambac Financial Group, Inc., (the "Company") has been taking a number of steps in consideration of a potential audit firm rotation. Of particular consideration is that recent acquisitions have resulted in the Company having multiple audit firms. KPMG LLP ("KPMG"), the Company's current independent registered public accounting firm, has served as the Company's auditor since 1985. Therefore, the Company and Audit Committee invited several independent registered public accounting firms, including KPMG, to respond to an audit services request for proposal ("RFP"). On December 10, 2025, the Company completed a competitive RFP process to determine the Company's independent registered public accounting firm for the fiscal year ending December 31, 2026. Following an extensive evaluation process and with the approval of the Audit Committee, the Company chose not to continue with the engagement of KPMG. The Company notified KPMG on December 10, 2025, that it will be dismissed as the Company's independent registered public accounting firm, upon completion of their audits of the Company's consolidated financial statements as of and for the year ended December 31, 2025, and the effectiveness of internal control over financial reporting as of December 31, 2025, and the issuance of their reports thereon. The audit reports of KPMG on the Ambac Financial Group, Inc. and subsidiaries' consolidated financial statements as of and f or the years ended December 31, 2024 and 2023, did not contain an adverse opinion or a disclaimer of opinion, and were not qualified or modified as to uncertainty, audit scope, or accounting principles. The audit reports of KPMG on the effectiveness of internal control

01. Financial Statements and Exhibits

Item 9.01. Financial Statements and Exhibits (d) Exhibits. The following exhibits are filed as part of this Current Report on Form 8-K 1 EXHIBIT INDEX Exhibit Number Exhibit Description 16.1 Letter from KPMG LLC dated December 15, 2025 99.1 Press Release dated December 15, 2025 101.INS XBRL Instance Document - the instance document does not appear in the interactive Data File because its XBRL tags are embedded within the Inline XBRL document. 101.SCH XBRL Taxonomy Extension Schema Document. 101.CAL XBRL Taxonomy Extension Calculation Linkbase Document. 101.LAB XBRL Taxonomy Extension Label Linkbase Document. 101.PRE XBRL Taxonomy Extension Presentation Linkbase Document. 101.DEF XBRL Taxonomy Extension Definition Linkbase Document. 104 Cover Page Interactive Data File - The cover page interactive data file does not appear in the Interactive Data File because its XBRL tags or embedded within the Inline XBRL document

SIGNATURES

SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Ambac Financial Group, Inc. (Registrant) Dated: December 15, 2025 By: /s/ William J. White William J. White First Vice President, Secretary and Assistant General Counsel 2

View Full Filing

View this 8-K filing on SEC EDGAR