X0202 SCHEDULE 13G 0001404574 XXXXXXXX LIVE Units (Class A Ordinary Shares, $0.0001 par vaue, and Redeemable Warrants) 08/27/2026 0002147219 Rainier Acquisition Corporation G73591110 1 PENN PLAZA, 48TH FLOOR NEW YORK NY 10119 Rule 13d-1(c) 683 Capital Management, LLC DE 0 862500 0 862500 862500 N 11.2 IA 683 Capital Partners, LP DE 0 862500 0 862500 862500 N 11.2 PN Ari Zweiman X1 0 862500 0 862500 862500 N 11.2 IN Rainier Acquisition Corporation 1 PENN PLAZA, 48TH FLOOR, NEW YORK, NEW YORK 10119 683 Capital Management, LLC 683 Capital Partners, LP Ari Zweiman Each of the foregoing is referred to as a "Reporting Person" and collectively as the "Reporting Persons." The principal business address for each of the Reporting Persons is 1700 Broadway, Suite 4200, New York, New York 10019. 683 Capital Management, LLC - DELAWARE 683 Capital Partners, LP - DELAWARE Ari Zweiman - UNITED STATES Y ** As of the date of this Schedule 13G, a CUSIP number for the issuer's Class A Ordinary Shares is not available. Initially, each of the Class A Ordinary Shares and warrants to purchase Class A Ordinary Shares will trade as a unit. The CUSIP number set forth herein is the CUSIP number for the issuer's units. As of August 27, 2026, 683 Capital Partners, LP beneficially owned 862,500 Class A Ordinary Shares. 683 Capital Management, LLC, as the investment manager of 683 Capital Partners, LP, may be deemed to have beneficially owned the 862,500 Class A Ordinary Shares beneficially owned by 683 Capital Partners, LP. Ari Zweiman, as the Managing Member of 683 Capital Management, LLC, may be deemed to have beneficially owned the 862,500 Class A Ordinary Shares beneficially owned by 683 Capital Management, LLC. The following percentage is based on 7,694,375 Class A Ordinary Shares outstanding as of August 27, 2026 which assumes no exercise of the underwriters' over-allotment option, as disclosed in the Issuer's Prospectus on Form 424(b)(4) (Registration Statement No. 333-298076) filed with the Securities and Exchange Commission on August 27, 2026. 11.2 See Cover Pages Items 5-9. See Cover Pages Items 5-9. See Cover Pages Items 5-9. See Cover Pages Items 5-9. Y Y Y N See Exhibit A. Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above 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. JOINT FILING AGREEMENT The undersigned hereby agree that the statement on Schedule 13G with respect to the Class A ordinary shares of Rainier Acquisition Corp dated as of September 3, 2026 is, and any further amendments thereto signed by each of the undersigned shall be, filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k)(2) under the Securities Exchange Act of 1934, as amended. Dated: September 3, 2026 683 CAPITAL MANAGEMENT, LLC By: /s/ Ari Zweiman Ari Zweiman, Managing Member 683 CAPITAL PARTNERS, LP By: /s/ Ari Zweiman Ari Zweiman, Authorized Person /s/ Ari Zweiman Ari Zweiman 683 Capital Management, LLC Ari Zweiman 09/03/2026 683 Capital Partners, LP Ari Zweiman 09/03/2026 Ari Zweiman Ari Zweiman 09/03/2026