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A holder of Pre-Funded Warrants may not exercise the Pre-Funded Warrant if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of outstanding shares of common stock of the Issuer immediately after giving effect to such exercise."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F3","text":"The Pre-Funded Warrants have no expiration date and are exercisable at any time after the date of issuance. A holder of Pre-Funded Warrants may not exercise the Pre-Funded Warrant if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of outstanding shares of common stock of the Issuer immediately after giving effect to such exercise."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Fairmount Funds Management LLC (\"Fairmount\") is the investment manager for Fairmount Healthcare Fund II L.P. and Fairmount Healthcare Co-Invest IV L.P. The managers of Fairmount are Peter Harwin and Tomas Kiselak. Fairmount, Mr. Harwin, and Mr. Kiselak disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein."}],"balance_after":855047,"derivative":{"exercise_price":0.0001,"underlying":"Common Stock","underlying_shares":855047},"source":{"system":"sec-edgar","filing":"0001104659-25-097921","document":"tm2528311-1_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2042283/000110465925097921/tm2528311-1_4seq1.xml","form_type":"4"}},{"id":1021656,"issuer":{"id":4757,"kind":"organization","name":"Jade Biosciences, Inc."},"owners":[{"id":2222,"kind":"person","name":"Fairmount Funds Management LLC","position":1,"cik":"0001802528","reported_name":"Fairmount Funds Management LLC","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}},{"id":2223,"kind":"person","name":"Fairmount Healthcare Fund II L.P.","position":2,"cik":"0001769651","reported_name":"Fairmount Healthcare Fund II L.P.","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}},{"id":39347,"kind":"person","name":"Fairmount Healthcare Co-Invest IV L.P.","position":3,"cik":"0002042283","reported_name":"Fairmount Healthcare Co-Invest IV L.P.","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}},{"id":2224,"kind":"person","name":"Kiselak Tomas","position":4,"cik":"0001830177","reported_name":"Kiselak Tomas","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}},{"id":2225,"kind":"person","name":"Harwin Peter Evan","position":5,"cik":"0001663607","reported_name":"Harwin Peter Evan","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2025-10-08T20:15:17.000Z","date":"2025-10-06","kind":"grant","planned":false,"acquired":true,"shares":1333126,"price":9.14,"value":12184771.64,"ownership":{"direct":false,"nature":"By Fairmount Healthcare Fund II L.P."},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The shares of Common Stock and Pre-Funded Warrants were purchased from the Issuer in a private placement, which transaction is exempt from Section 16(b) in accordance with Rule 16b-3(d)(1) promulgated under the Securities Exchange Act of 1934, as amended."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Fairmount Funds Management LLC (\"Fairmount\") is the investment manager for Fairmount Healthcare Fund II L.P. and Fairmount Healthcare Co-Invest IV L.P. The managers of Fairmount are Peter Harwin and Tomas Kiselak. Fairmount, Mr. Harwin, and Mr. Kiselak disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein."}],"balance_after":1897677,"source":{"system":"sec-edgar","filing":"0001104659-25-097921","document":"tm2528311-1_4seq1.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2042283/000110465925097921/tm2528311-1_4seq1.xml","form_type":"4"}}]}