X0508 4 2023-08-14 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 Stock Option (Right to Buy) 25.71 2023-08-14 4 A 0 20000 0 A 2033-08-14 American Depositary Shares 20000 20000 D Restricted Share Units 2023-08-14 4 A 0 5000 0 A American Depositary Shares 5000 5000 D Each Stock Option is exercisable for one American Depositary Share (ADS), which represents ten Ordinary Shares of the issuer. The option vests in equal annual installments over four years beginning on 08/14/2024, the first anniversary of the date of grant. Each 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. Each Restricted Share Unit represents a contingent right to receive one ADS, which represents ten Ordinary Shares of the issuer. The Restricted Share Units vest in equal annual installments over four years beginning on 08/14/2024, the first anniversary of the date of grant. Vested shares will be delivered to the reporting person following vesting. /s/ Bruce Blefeld, Attorney-in-Fact 2023-08-21