Zai Lab Ltd

The Company may satisfy SEC rules regarding delivery of proxy materials, including this Proxy Statement, by delivering a single set of proxy materials to an address shared by two or more Company shareholders. This delivery method can result in meaningful cost savings for the Company. In order to take advantage of this opportunity, the Company may deliver only a single set of proxy materials to multiple shareholders who share an address, unless contrary instructions are received prior to the mailing date. Similarly, if you share an address with another shareholder and have received multiple copies of our proxy materials, you may write or call us at the address and phone number below to request delivery of a single copy of the proxy materials in the future. We undertake to deliver promptly upon written or oral request a separate copy of the proxy materials, as requested, to a shareholder at a shared address to which a single copy of the proxy materials was delivered. If you hold ordinary shares as a record shareholder in Hong Kong or Cayman Islands and prefer to receive separate copies of proxy materials either now or in the future, please contact Zai Lab Limited at 314 Main Street, Fourth Floor, Suite 100, Cambridge, MA 02142, Attention: Corporate Secretary, +86 21 6163 2588 or +1 (786) 250-1886. If you hold ordinary shares in the form of ADSs issued by Citibank (the depositary of our ADSs), or hold ordinary shares through a brokerage firm or bank and you prefer to receive separate copies of proxy materials either now or in the future, please contact Citibank (the depositary of our ADSs), or your brokerage firm or bank, as applicable.

Generally, shareholders who have questions or concerns should contact our Investor Relations department at 4560 Jinke Road, Bldg. 1, Fourth Floor, Pudong, Shanghai, China 201210. However, shareholders who wish to communicate directly with the Board of Directors, or any individual director, should direct questions in writing to our Chief Legal Officer & Corporate Secretary at 314 Main Street, Fourth Floor, Suite 100, Cambridge, MA 02142. Communications addressed in this manner will be forwarded directly to the Board of Directors or named individual director(s), as appropriate.

EACH SHAREHOLDER IS URGED TO COMPLETE, DATE, SIGN, AND

PROMPTLY RETURN THE ENCLOSED PROXY CARD

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