X0508 4 2025-06-02 0001704292 Zai Lab Ltd ZLAB 0001985694 Chen Yajing C/O ZAI LAB LIMITED 314 MAIN STREET, 4TH FLOOR, SUITE 100 CAMBRIDGE MA 02142 true Chief Financial Officer true American Depositary Shares 2025-06-02 4 S 0 9618 30 D 17429 D Each American Depositary Share ("ADS") represents ten Ordinary Shares of the issuer. Our ADSs and Ordinary Shares are fully fungible. For purposes of this Form 4, we are reporting this in terms of ADSs. The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 3, 2025. /s/ Bruce Blefeld, Attorney-in-Fact 2025-06-04