X0609 4 2026-03-04 0001704292 Zai Lab Ltd ZLAB 0001985694 Chen Yajing false C/O ZAI LAB LIMITED 314 MAIN STREET, 4TH FLOOR, SUITE 100 CAMBRIDGE MA 02142 false true false false Chief Financial Officer false American Depositary Shares 2026-04-01 4 M false 1500 A 21499 D American Depositary Shares 2026-04-01 4 M false 13758 A 35257 D American Depositary Shares 2026-04-02 4 M false 2500 A 37757 D American Depositary Shares 2026-04-02 4 S false 5199 20.39 D 32558 D Performance-Based Share Units 2026-03-04 4 A false 11924 0 A American Depositary Shares 11924 11924 D Restricted Share Units 2026-04-01 4 M false 1500 0 D American Depositary Shares 1500 1500 D Restricted Share Units 2026-04-01 4 M false 13758 0 D American Depositary Shares 13758 27516 D Restricted Share Units 2026-04-02 4 M false 2500 0 D American Depositary Shares 2500 2500 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 upon vesting of Restricted Share Units ("RSUs"). Each RSU represents a contingent right to receive one ADS. These ADSs were sold automatically to cover taxes upon vesting of RSUs. Each performance-based share unit ("PSU") represents a contingent right to receive one ADS. The reporting person was granted PSUs on March 12, 2025 based on the satisfaction of specified performance criteria between January 1, 2025 through December 31, 2025. On March 4, 2026, the performance-based vesting conditions were confirmed for PSUs representing 11,924 ADSs. The PSUs vest in full on March 12, 2028, the third anniversary of the date of grant, subject to continuous service. The RSUs vest in equal annual installments over five years beginning on 04/01/2023, the first anniversary of the date of grant, subject to continuous service. Vested shares will be delivered in the form of ADSs to the reporting person following vesting. 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 in the form of ADSs to the reporting person following vesting. The RSUs vest in equal annual installments over four years beginning on 04/03/2024, the first anniversary of the date of grant, subject to continuous service. Vested shares will be delivered in the form of ADSs to the reporting person following vesting. /s/ Bruce Blefeld, Attorney-in-Fact 2026-04-03