AMBC amends charter and bylaws to adopt Octave Specialty name

Rhea-AI Filing Summary

Ambac Financial Group, Inc. reported a corporate rebranding. On November 10, 2025, the company filed a certificate of amendment with Delaware authorities to change its name to Octave Specialty Group, Inc.

In connection with the name change, the company’s bylaws were amended and restated to reflect the new corporate name. Supporting documents include the Amended and Restated Certificate of Incorporation (Exhibit 3.1), Amended and Restated Bylaws (Exhibit 3.2), and a press release dated November 10, 2025 (Exhibit 99.1). The company’s common stock is listed on the NYSE under the symbol AMBC.

8-K Event Classification

2 items: 5.03, 9.01

2 items

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year Governance

The company amended its charter documents, bylaws, or changed its fiscal year.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, and exhibit attachments filed with this report.

Understanding 8-K Material Events →

0000874501FALSE12/3100008745012025-11-102025-11-10

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): November 10, 2025

Ambac Financial Group, Inc.

(Exact name of Registrant as specified in its charter)

Delaware

1-10777

13-3621676

(State of incorporation)

(Commission file number)

(I.R.S. employer identification no.)

One World Trade Center			New York			NY			10007
(Address of principal executive offices)

			(212)			658-7470
(Registrant's telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the Registrant under any of the following provisions:

☐			Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐			Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐			Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐			Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol

Name of each exchange on which registered

Common stock, par value $0.01 per share

AMBC

New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 under the Securities Act (17 CFR 230.405) or Rule 12b-2 under the Exchange Act (17 CFR 240.12b-2).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to
Section 13(a) of the Exchange Act.			☐

Item 5.03. Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year

On November 10, 2025, the Company filed with the Secretary of State of the State of Delaware a certificate of amendment to its certificate of incorporation, changing the Company’s name to “Octave Specialty Group, Inc.” (the “Name Change”). A copy of the Amended and Restated Certificate of Incorporation is filed as Exhibit 3.1 hereto, which is incorporated by reference into this Item 5.03. In connection with the Name Change, the bylaws of the Company were amended and restated in their entirety to reflect the Name Change. A copy of the Amended and Restated Bylaws is filed as Exhibit 3.2 hereto, which is incorporated by reference into this Item 5.03.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits. The following exhibits are filed as part of this Current Report on Form 8-K

EXHIBIT INDEX

Exhibit Number

Exhibit Description

3.1

Amended and Restated Certificate of Incorporation of Octave Specialty Group, Inc.

3.2

Amended and Restated Bylaws of Octave Specialty Group, Inc.

99.1

Press Release dated November 10, 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

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:

November 10, 2025

By:

/s/ William J. White

William J. White

First Vice President, Secretary and Assistant General Counsel

1

FAQ

What did AMBC announce in this 8-K?

The company filed a certificate of amendment to change its name to Octave Specialty Group, Inc. and restated its bylaws to reflect the name change.

When was the name change filing made for AMBC?

It was filed on November 10, 2025 with the Delaware Secretary of State.

What is Ambac’s new corporate name?

Ambac changed its corporate name to Octave Specialty Group, Inc.

Were AMBC’s bylaws affected by this change?

Yes. The bylaws were amended and restated to reflect the new name.

Which exhibits were filed with this report?

Exhibit 3.1 (Amended and Restated Certificate of Incorporation), Exhibit 3.2 (Amended and Restated Bylaws), and Exhibit 99.1 (Press Release dated November 10, 2025).

What exchange and symbol are listed for the company?

Common stock is listed on the New York Stock Exchange under the symbol AMBC.

Who signed the report for AMBC?

William J. White, First Vice President, Secretary and Assistant General Counsel, signed the report on November 10, 2025.