SCHEDULE 13G 0002078270 XXXXXXXX LIVE Class A common shares, $0.0000011951862 par value per share 09/30/2025 0001997350 Accelerant Holdings G00894108 Unit 106, Windward 3 Regatta Office Park, West Bay Road Grand Cayman E9 KY1-1108 Rule 13d-1(d) ACP Accelerant Holdings, L.P. E9 0 85976902 0 85976902 85976902 N 42.9 PN See Item 4 ACP Insurance Management, LLC E9 0 90916741 0 90916741 90916741 N 44.2 OO See Item 4 Schwartz Keoni Andrew X1 0 90916741 0 90916741 90916741 N 44.2 IN HC See Item 4 Accelerant Holdings Unit 106, Windward 3, Regatta Office Park, West Bay Road, Grand Cayman, Cayman Islands, KY1-1108 This Statement is filed by Keoni Schwartz ("Mr. Schwartz"), ACP Accelerant Holdings, L.P., and ACP Insurance Management, LLC. (together, the "Reporting Persons"). The Class A common shares reported as beneficially owned by the Reporting Persons herein consist entirely of Class A common shares underlying Class B common shares that are held directly by ACP Accelerant Holdings, L.P., ACP Accelerant Co-Invest, LLC, and ACP Accelerant Investment Holding Company II, Ltd. Each holder of Class B common shares has the right to convert their Class B common shares into Class A common shares on a 1-for-1 basis at any time and at their option. Additionally, the Class B common shares will automatically convert into Class A common shares, on a 1-for-1 basis, immediately following a transfer to any non-permitted holder of Class B common shares, and all outstanding Class B common shares will automatically convert into Class A common shares, on a 1-for-1 basis, on the earlier of (i) if at any time following the consummation of the Issuer's initial public offering, the holders of the Class B common shares immediately prior to the consummation of the initial public offering hold less than 50% of the total Class B common shares then in issue, and (ii) July 25, 2028, which is the third anniversary of the date on which the Issuer consummated its initial public offering. ACP Accelerant Holdings, L.P. is the sole owner of ACP Accelerant Investment Holding Company II, Ltd. As such, ACP Accelerant Holdings, L.P. may be deemed to beneficially own the Class A common shares underlying the Class B common shares held directly by ACP Accelerant Holdings, L.P. and ACP Accelerant Investment Holding Company II, Ltd. ACP Insurance Management, LLC is the general partner of ACP Accelerant Holdings, L.P. and the managing member of ACP Accelerant Co-Invest, LLC. As such, ACP Insurance Management, LLC may be deemed to beneficially own the Class A common shares underlying the Class B common shares held directly by ACP Accelerant Holdings, L.P., ACP Accelerant Investment Holding Company II, Ltd., and ACP Accelerant Co-Invest, LLC. Mr. Schwartz is the sole owner and managing member of ACP Insurance Management, LLC. As such, Mr. Schwartz may be deemed to beneficially own the Class A common shares underlying the Class B common shares held directly by ACP Accelerant Holdings, L.P., ACP Accelerant Investment Holding Company II, Ltd., and ACP Accelerant Co-Invest, LLC. 400 Hamilton Avenue, Suite 230, Palto Alto, CA 94301 Mr. Schwartz is a citizen of the United States. ACP Accelerant Holdings, L.P. is a Cayman Islands limited partnership. ACP Insurance Management, LLC is a Cayman Islands limited liability company. Y As of September 30, 2025, ACP Accelerant Holdings, L.P. may be deemed the beneficial owner of 85,976,902 Class A common shares. This amount includes (i) 82,674,639 Class A common shares it has the right to acquire upon conversion of 82,674,639 Class B common shares held directly by ACP Accelerant Holdings, L.P. and (ii) 3,302,263 Class A common shares it has the right to acquire upon conversion of 3,302,263 Class B common shares held directly by ACP Accelerant Investment Holding Company II, Ltd. As of September 30, 2025, ACP Insurance Management, LLC and Mr. Schwartz may be deemed the beneficial owners of 90,916,741 Class A common shares. This amount includes (i) 82,674,639 Class A common shares they have the right to acquire upon conversion of 82,674,639 Class B common shares held directly by ACP Accelerant Holdings, L.P., (ii) 3,302,263 Class A common shares they have the right to acquire upon conversion of 3,302,263 Class B common shares held directly by ACP Accelerant Investment Holding Company II, Ltd., and (iii) 4,939,839 Class A common shares they have the right to acquire upon conversion of 4,939,839 Class B common shares held directly by ACP Accelerant Co-Invest, LLC. As of September 30, 2025, ACP Accelerant Holdings, L.P. may be deemed to beneficially own approximately 42.9% of the Class A common shares outstanding. This percentage is based on (i) 114,578,616 Class A common shares outstanding as of September 30, 2025, as reported in the Issuer's quarterly report on Form 10-Q filed with the Securities and Exchange Commission on November 12, 2025 (the "Q3 2025 Form 10-Q"), and (ii) an aggregate 85,976,902 Class A common shares it has the right to acquire upon conversion of an aggregate 85,976,902 Class B common shares held directly by ACP Accelerant Holdings, L.P. and ACP Accelerant Investment Holding Company II, Ltd., which Class A common shares have been added to the quantity of Class A common shares outstanding in accordance with Rule 13d-3(d)(1)(i) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"). As of September 30, 2025, ACP Insurance Management, LLC and Mr. Schwartz may be deemed to beneficially own approximately 44.2% of the Class A common shares outstanding. This percentage is based on (i) 114,578,616 Class A common shares outstanding as of September 30, 2025, as reported in the Q3 2025 Form 10-Q, and (ii) an aggregate 90,916,741 Class A common shares they have the right to acquire upon conversion of an aggregate 90,916,741 Class B common shares held directly by ACP Accelerant Holdings, L.P., ACP Accelerant Investment Holding Company II, Ltd., and ACP Accelerant Co-Invest, LLC, which Class A common shares have been added to the quantity of Class A common shares outstanding in accordance with Rule 13d-3(d)(1)(i) under the Exchange Act. The Issuer has two classes of Common Stock: Class A common shares and Class B common shares. Each Class A common share is entitled to one vote per share, and each Class B common share is entitled to ten votes per share. Accordingly, ACP Accelerant Holdings, L.P.'s percentage ownership of the aggregate Class A common shares and Class B common shares outstanding is approximately 38.8%, and its aggregate voting power represents approximately 72.4% of the voting power of the Issuer. ACP Insurance Management, LLC's and Mr. Schwartz's percentage ownership of the aggregate Class A common shares and Class B common shares outstanding is approximately 41.0%, and their aggregate voting power represents approximately 76.6% of the voting power of the Issuer. The aggregate percentage ownership of the Class A common shares and Class B common shares and the aggregate voting power set forth herein are based on 114,578,616 Class A common shares and 107,241,428 Class B common shares, each outstanding as of September 30, 2025, as reported in the Q3 2025 Form 10-Q. ACP Accelerant Holdings, L.P.: 0 ACP Insurance Management, LLC: 0 Mr. Schwartz: 0 ACP Accelerant Holdings, L.P.: 85,976,902 ACP Insurance Management, LLC: 90,916,741 Mr. Schwartz: 90,916,741 ACP Accelerant Holdings, L.P.: 0 ACP Insurance Management, LLC: 0 Mr. Schwartz: 0 ACP Accelerant Holdings, L.P.: 85,976,902 ACP Insurance Management, LLC: 90,916,741 Mr. Schwartz: 90,916,741 Y N The responses to Items 2 and 4 are incorporated herein by reference. N The response to Item 2(a) is incorporated herein by reference. Y Y Y Exhibit 1: Joint Filing Agreement, dated November 14, 2025 Exhibit 2: Power of Attorney for ACP Accelerant Holdings, L.P., dated July 22, 2025 Exhibit 3: Power of Attorney for ACP Insurance Management, LLC, dated July 22, 2025 Exhibit 4: Power of Attorney for Keoni Andrew Schwartz, dated September 19, 2025 ACP Accelerant Holdings, L.P. /s/ Jennifer Mello 11/14/2025 ACP Insurance Management, LLC /s/ Jennifer Mello 11/14/2025 Schwartz Keoni Andrew /s/ David Pelsue 11/14/2025