SCHEDULE 13D/A 0001352851 XXXXXXXX LIVE 1 Class A Common Stock, par value $0.001 01/26/2026 false 0001454789 04635X102 Astria Therapeutics, Inc.

22 BOSTON WHARF ROAD, 10TH FLOOR BOSTON MA 02210

David J. Snyderman 847-905-4400 1603 Orrington Avenue 13th Floor Evanston IL 60201 0001352851 N Magnetar Financial LLC b OO N DE 0.00 0.00 0.00 0.00 0.00 N 0 IA OO 0001353085 N Magnetar Capital Partners LP b OO N DE 0.00 0.00 0.00 0.00 0.00 N 0 HC OO 0001368026 N Supernova Management LLC b OO N DE 0.00 0.00 0.00 0.00 0.00 N 0 HC OO 0001953511 N David J. Snyderman b OO N X1 0.00 0.00 0.00 0.00 0.00 N 0 IN HC Class A Common Stock, par value $0.001 Astria Therapeutics, Inc. 22 BOSTON WHARF ROAD, 10TH FLOOR BOSTON MA 02210 Since the filing of the Reporting Persons' Form 13D Report of the Issuer on October 24, 2025, the Reporting Persons have purchased 118,805 Shares on behalf of the Funds. The aggregate amount of funds used by the Reporting Persons in purchasing the 118,805 Shares reported herein on behalf of the Funds have come directly from the assets of the Funds, which may any given time, have included margin loans made by brokerage firms in the ordinary course of business. The aggregate amount of funds used by the Reporting Persons was $1,501,294.83 (excluding commissions and other execution-related costs). Since the filing of the Schedule 13D on October 24, 2025, on January 23, 2026, the Issuer consummated a merger (the "Merger") pursuant to which each issued and outstanding Share was cancelled and converted into the right to receive $8.55 in cash, without interest. In connection with the Merger, the Reporting Persons' 3,431,007 Shares, which consisted of 1,560,502 Shares sold for the benefit of PRA Master Fund; 804,159 Shares sold for the benefit of Systematic Master Fund; 221,576 Shares sold for the benefit of the Relative Value Master Fund and 844,770 Shares sold for the benefit of two Managed Accounts, were cancelled and converted into the right to receive $8.55 in cash, without interest. As of the closing of the Merger on January 23, 2026, each of the Reporting Persons may have been deemed to have beneficial ownership of 0 Shares. As of the closing of the Merger on January 23, 2026, each of the Reporting Persons may have been deemed to share the power to vote and direct the disposition of 0 Shares, which represented beneficial ownership of 0% of the Shares. Except as set forth on Schedule A attached hereto and Item 6, the Funds had no transactions in the Shares during the 60 days preceding the date of filing of this Statement. All of the transactions set forth on Schedule A attached hereto were effected in the ordinary course of business of Magnetar Financial for the accounts of each of the Funds. The transactions in the Shares set forth on Schedule A were effected in open market transactions on the NASDAQ and various other trading markets. 01-26-2026 99.1 Joint Filing Agreement, dated as of January 28, 2026, among the Reporting Persons. 99.2 Power of Attorney, dated as of December 22, 2022 filed by the Reporting Persons on January 28, 2026. 99.3 Schedule A, dated as of January 28, 2026. Magnetar Financial LLC /s/ Hayley Stein 01/28/2026 Magnetar Capital Partners LP /s/ Hayley Stein 01/28/2026 Supernova Management LLC /s/ Hayley Stein 01/28/2026 David J. Snyderman /s/ Hayley Stein 01/28/2026 MAGNETAR FINANCIAL LLC BY: Magnetar Capital Partners LP, its Sole Member BY: Supernova Management LLC, its General Partner MAGNETAR CAPITAL PARTNERS LP By: Supernova Management LLC, its General Partner