# EDGAR Filing Document

**Accession Number:** 0000874501
**File Stem:** 0001628280-26-024691
**Filing Date:** 2026-4
**Character Count:** 8950
**Document Hash:** 24a170c36d0f03b3a960656e8884c39f
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001628280-26-024691.hdr.sgml**: 20260410

**ACCESSION NUMBER**: 0001628280-26-024691

**CONFORMED SUBMISSION TYPE**: DEFA14A

**PUBLIC DOCUMENT COUNT**: 6

**FILED AS OF DATE**: 20260410

**DATE AS OF CHANGE**: 20260410

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** OCTAVE SPECIALTY GROUP INC
- **CENTRAL INDEX KEY:** 0000874501
- **STANDARD INDUSTRIAL CLASSIFICATION:** SURETY INSURANCE [6351]
- **ORGANIZATION NAME:** 02 Finance
- **EIN:** 133621676
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** DEFA14A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-10777
- **FILM NUMBER:** 26855002

**BUSINESS ADDRESS:**
- **STREET 1:** 40 WALL STREET
- **STREET 2:** 55TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10005
- **BUSINESS PHONE:** 2126587470

**MAIL ADDRESS:**
- **STREET 1:** 40 WALL STREET
- **STREET 2:** 55TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10005

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AMBAC FINANCIAL GROUP INC
- **DATE OF NAME CHANGE:** 19980121

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AMBAC INC /DE/
- **DATE OF NAME CHANGE:** 19930328

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

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| | |
|:---|:---|
| | **SCHEDULE 14A INFORMATION** |
| **PROXY STATEMENT PURSUANT TO SECTION 14(A) OF** | **PROXY STATEMENT PURSUANT TO SECTION 14(A) OF** |
| **THE SECURITIES EXCHANGE ACT OF 1934** | **THE SECURITIES EXCHANGE ACT OF 1934** |
| **(AMENDMENT NO. ____)** | **(AMENDMENT NO. ____)** |

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Filed by the Registrant ☒ Filed by a Party other than the Registrant ¨

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| | |
|:---|:---|
| Check the appropriate box: | Check the appropriate box: |
| ◻ | Preliminary Proxy Statement |
| ◻ | **Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))** |
| ◻ | Definitive Proxy Statement |
| ⌧ | Definitive Additional Materials |
| ◻ | Soliciting Material Pursuant to §240.14a-12 |

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| |
|:---|
| **OCTAVE SPECIALTY GROUP, INC.** |
| **(Name of Registrant as Specified In Its Charter)** |
| **(Name of Person(s) Filing Proxy Statement, if Other Than the Registrant)**  |

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| | | |
|:---|:---|:---|
| PAYMENT OF FILING FEE (CHECK THE APPROPRIATE BOX): | PAYMENT OF FILING FEE (CHECK THE APPROPRIATE BOX): | PAYMENT OF FILING FEE (CHECK THE APPROPRIATE BOX): |
| ⌧ | No fee required. | No fee required. |
| ◻ | Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11. | Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11. |
| | (1) | Title of each class of securities to which the transaction applies: |
| | (2) | Aggregate number of securities to which the transaction applies: |
| | (3) | Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (set forth the amount on which the filing fee is calculated and state how it was determined): |
| | (4) | Proposed maximum aggregate value of transaction: |
| | (5) | Total fee paid: |
| ◻ | Fee paid previously with preliminary materials. | Fee paid previously with preliminary materials. |
| ◻ | Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing. | Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing. |
| | (1) | Amount previously paid: |
| | (2) | Form, Schedule or Registration Statement No.: |
| | (3) | Filing Party: |
| | (4) | Date Filed: |

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**Vote at www.ProxyVote.com**

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| | |
|:---|:---|
| | Your **Vote** Counts! |
| | **OCTAVE SPECIALTY GROUP, INC.** |
| | **2026 Annual Meeting** |
| | **Vote by May 27, 2026** |
| | **11:59 PM ET** |
| | ![votingmachinea.jpg](votingmachinea.jpg) |
| | ![votingmachinea.jpg](votingmachinea.jpg) |
| OCTAVE SPECIALTY GROUP, INC.<br>REID POWELL<br>40 WALL STREET<br>NEW YORK, NY 10005 | ![votingmachinea.jpg](votingmachinea.jpg) |
| OCTAVE SPECIALTY GROUP, INC.<br>REID POWELL<br>40 WALL STREET<br>NEW YORK, NY 10005 | ![votingmachinea.jpg](votingmachinea.jpg) |
| OCTAVE SPECIALTY GROUP, INC.<br>REID POWELL<br>40 WALL STREET<br>NEW YORK, NY 10005 | ![votingmachinea.jpg](votingmachinea.jpg) |
|  | ![votingmachinea.jpg](votingmachinea.jpg) |
|  | ![votingmachinea.jpg](votingmachinea.jpg) |
|  | ![votingmachinea.jpg](votingmachinea.jpg) |
|  | ![votingmachinea.jpg](votingmachinea.jpg) |
|  | ![votingmachinea.jpg](votingmachinea.jpg) |
| V90538-P51042 |  |

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You invested in **OCTAVE SPECIALTY GROUP, INC.** and it's time to vote!

You have the right to vote on proposals being presented at the Annual Meeting of Stockholders. **This is an important notice regarding the availability of proxy material for the stockholder meeting to be held on May 28, 2026.**

**Get informed before you vote**

View the Annual Report, Notice & Proxy Statement online OR you can receive a free paper or email copy of the material(s) by requesting a copy prior to May 14, 2026. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy.

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| | |
|:---|:---|
| ![pv.jpg](pv.jpg) | |
| ![pv.jpg](pv.jpg) | For complete information and to vote, visit **www.ProxyVote.com** |
| ![pv.jpg](pv.jpg) | Control # |
| ![pv.jpg](pv.jpg) | |

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| | | |
|:---|:---|:---|
| **Smartphone users** | ![virtualvotejpga.jpg](virtualvotejpga.jpg) | **Vote Virtually at the Meeting\*** |
| Point your camera here and | ![virtualvotejpga.jpg](virtualvotejpga.jpg) | May 28, 2026 |
| vote without entering a | ![virtualvotejpga.jpg](virtualvotejpga.jpg) | 11:00 A.M. Eastern Time |
| control number | ![virtualvotejpga.jpg](virtualvotejpga.jpg) | |
| ![arrowjpga.jpg](arrowjpga.jpg) | Virtually at: |  |
| ![arrowjpga.jpg](arrowjpga.jpg) | www.virtualshareholdermeeting.com/OSG2026 | www.virtualshareholdermeeting.com/OSG2026 |

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\*Please check the meeting materials for any special requirements for meeting attendance

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**Vote at www.ProxyVote.com**

**THIS IS NOT A VOTABLE BALLOT**

This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote on these important matters.

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| | | | |
|:---|:---|:---|:---|
| **Voting Items** | **Voting Items** | **Board<br>Recommends** | **Board<br>Recommends** |
| 1 | Election of Directors |  |  |
|  | **Nominees:** |  |  |
| 1a. | Ian D. Haft | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| 1b. | Lisa G. Iglesias | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| 1c. | Joan Lamm-Tennant | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| 1d. | Claude LeBlanc | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| 1e. | Kristi A. Matus | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| 1f. | Michael D. Price | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| 1g. | Jeffrey S. Stein | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| 2 | To approve, on a non-binding advisory basis, the compensation for our named executive officers | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| 3 | To ratify the appointment of Ernst & Young as Octave's independent registered public accounting firm for the fiscal<br>year ending December 31, 2026 | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| 4 | To approve Octave's 2026 Incentive Compensation Plan | ![checkmarkjpga.jpg](checkmarkjpga.jpg) | **For** |
| **NOTE:** Any action on the items of business described above may be considered at the Annual Meeting at the time and on the date specified above or at any time and date to which the Annual Meeting may be properly adjourned or postponed. | **NOTE:** Any action on the items of business described above may be considered at the Annual Meeting at the time and on the date specified above or at any time and date to which the Annual Meeting may be properly adjourned or postponed. |  |  |
| Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click "Delivery Settings". | Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click "Delivery Settings". | Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click "Delivery Settings". |  |

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V90539-P51042