Zai Lab Limited (Zai Lab) has closed its previously announced private placement of 11.34 million American depositary shares (ADSs), each representing ten ordinary shares, on 27 October 2026 (U.S. Eastern Time). Leerink Partners LLC acted as the exclusive placement agent.

Transaction Terms • Issue price: USD 22.04 per ADS, equivalent to HKD 17.28 per underlying ordinary share. • Pricing represented a 7.13% discount to the HKD 18.61 average closing price of Zai Lab’s Hong Kong-listed shares over the five trading days prior to 23 October 2026. • Gross proceeds: USD 249.93 million (HKD 1.96 billion). • Net proceeds (after placement agent fees and expenses): USD 241.17 million (HKD 1.89 billion).

Intended Use of Proceeds Management plans to allocate the net proceeds primarily to advance the global development of zocilurtatug pelitecan (zoci), the company’s Delta-like ligand 3 (DLL3)-targeting antibody-drug conjugate under investigation for extensive-stage small cell lung cancer.

Post-Placement Shareholding Structure • Total ordinary shares outstanding: 1,251.23 billion. • Core connected persons: 60.50 million shares (4.84%). • New placement investors: 113.40 million shares (9.06%). • Other public shareholders: 1,077.33 million shares (86.10%). Zai Lab confirmed that the public float remains above the minimum thresholds set by the Hong Kong Listing Rules.

Governance The board continues to be chaired by Director and CEO Dr. Samantha Du, supported by one additional director and seven independent directors.

Timing Completion of the transaction occurred four days after the securities purchase agreement was executed on 23 October 2026.

Currency Translation US dollar figures were converted at USD 1 = HKD 7.84, the rate disclosed in the announcement.

Forward-Looking Considerations The company highlights customary forward-looking uncertainties related to product development, regulatory approvals, and financing, as detailed in its filings with the U.S. Securities and Exchange Commission.