X0407 4 2023-03-31 0 0001704292 Zai Lab Ltd ZLAB 0001731790 Du Ying C/O ZAI LAB LIMITED 314 MAIN STREET, 4TH FLOOR, SUITE 100 CAMBRIDGE MA 02142 1 1 0 0 Chairperson & CEO 0 American Depositary Shares 2023-03-31 4 M 0 3400 33.26 A 997489 D American Depositary Shares 2023-03-31 4 F 0 1338 33.26 D 996151 D American Depositary Shares 2023-03-31 4 M 0 10800 33.26 A 1006951 D American Depositary Shares 2023-03-31 4 F 0 4250 33.26 D 1002701 D Restricted Share Units 2023-03-31 4 M 0 10800 0.00 D American Depositary Shares 10800 43200 D Restricted Share Units 2023-03-31 4 M 0 3400 0.00 D American Depositary Shares 3400 10200 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. Each ADS represents ten Ordinary Shares of the issuer. This transaction represents the disposition of shares to cover taxes. 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 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. The Restricted Share Units vest in equal annual installments over five years beginning on 04/01/2022, 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 2023-04-03