SCHEDULE 13G/A 0001446580-25-000061 0001446580 XXXXXXXX LIVE 1 Common Stock, $0.01 par value per share 09/30/2025 0000874501 Ambac Financial Group, Inc. 023139884 One World Trade Center New York NY 10007 Rule 13d-1(b) G1 Execution Services, LLC IL 5098 1017308 5098 1017308 1017308 2.2 BD OO With respect to Row 5 through Row 9 above, G1 Execution Services, LLC, SIG Brokerage, LP and Susquehanna Securities, LLC are affiliated independent broker-dealers which may be deemed a group. For purposes of this report, we have indicated that each reporting person has sole voting and dispositive power with respect to the shares beneficially owned by it and that the reporting persons have shared voting and dispositive power with respect to all shares beneficially owned by all of the reporting persons. Each of the reporting persons disclaims beneficial ownership of shares owned directly by another reporting person. SIG Brokerage, LP DE 2500 1017308 2500 1017308 1017308 2.2 BD PN With respect to Row 5 through Row 9 above, G1 Execution Services, LLC, SIG Brokerage, LP and Susquehanna Securities, LLC are affiliated independent broker-dealers which may be deemed a group. For purposes of this report, we have indicated that each reporting person has sole voting and dispositive power with respect to the shares beneficially owned by it and that the reporting persons have shared voting and dispositive power with respect to all shares beneficially owned by all of the reporting persons. Each of the reporting persons disclaims beneficial ownership of shares owned directly by another reporting person. Susquehanna Securities, LLC DE 1009710 1017308 1009710 1017308 1017308 2.2 BD OO With respect to Row 5 through Row 9 above, G1 Execution Services, LLC, SIG Brokerage, LP and Susquehanna Securities, LLC are affiliated independent broker-dealers which may be deemed a group. For purposes of this report, we have indicated that each reporting person has sole voting and dispositive power with respect to the shares beneficially owned by it and that the reporting persons have shared voting and dispositive power with respect to all shares beneficially owned by all of the reporting persons. Each of the reporting persons disclaims beneficial ownership of shares owned directly by another reporting person. This statement is filed by the entities listed below, who are collectively referred to herein as "Reporting Persons" with respect to the shares of Common Stock, $0.01 par value per share (the "Shares"), of Ambac Financial Group, Inc. (the "Company"). (i) G1 Execution Services, LLC (ii) SIG Brokerage, LP (iii) Susquehanna Securities, LLC The address of the principal business office of G1 Execution Services, LLC is: 175 W. Jackson Blvd. Suite 1700 Chicago, IL 60604 The address of the principal business office of each of SIG Brokerage, LP and Susquehanna Securities, LLC is: 401 E. City Avenue Suite 220 Bala Cynwyd, PA 19004 Citizenship is set forth in Row 4 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person. N BD The information required by this Item 4(a) is set forth in Row 9 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person. The number of Shares reported as beneficially owned by Susquehanna Securities, LLC includes options to buy 735,400 Shares. The Company's Quarterly Report on Form 10-Q, filed on August 7, 2025, indicates that there were 46,401,736 Shares outstanding as of August 5, 2025. 2.2% The information required by this Item 4(c)(i) is set forth in Row 5 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person. The information required by this Item 4(c)(ii) is set forth in Row 6 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person. The information required by this Item 4(c)(iii) is set forth in Row 7 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person. The information required by this Item 4(c)(iv) is set forth in Row 8 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person. N Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. EXHIBIT INDEX EXHIBIT DESCRIPTION ________ ________ 99 Joint Filing Agreement G1 Execution Services, LLC /s/ Brian Sopinsky 11/13/2025 SIG Brokerage, LP /s/ Brian Sopinsky 11/13/2025 Susquehanna Securities, LLC /s/ Brian Sopinsky 11/13/2025