X0508 4 2024-04-01 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 false American Depositary Shares 2024-04-01 4 M 0 1500 16.72 A 8482 D American Depositary Shares 2024-04-02 4 S 0 519 16.151 D 7963 D Stock Options (Right to Buy) 16.72 2024-04-01 4 A 0 84663 0 A 2034-04-01 American Depositary Shares 84663 84663 D Restricted Share Units 2024-04-01 4 A 0 55031 0 A American Depositary Shares 55031 55031 D Restricted Share Units 2024-04-01 4 M 0 1500 0 D American Depositary Shares 1500 4500 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. ADSs acquired on vesting of Restricted Share Units. These ADSs were sold automatically to cover taxes upon vesting of Restricted Share Units. Each Stock Option is exercisable for one ADS, which represents ten Ordinary Shares of the issuer. The option vests in equal annual installments over four years beginning on 04/01/2025, the first anniversary of the date of grant, subject to continuous service. Each Restricted Share Unit ("RSU") represents a contingent right to receive one ADS, which represents ten Ordinary Shares of the issuer. The RSUs vest in equal annual installments over four years beginning on 04/01/2025, the first anniversary of the date of grant, subject to continuous service. Vested shares will be delivered to the reporting person following vesting. The RSUs vest in equal annual installments over five years beginning on 04/01/2023, the first anniversary of the date of grant. Vested shares will be delivered in the form of ADSs to the reporting person following vesting. /s/ Bruce Blefeld, Attorney-in-Fact 2024-04-03