Sec Form 4/A Filing - Du Ying @ Zai Lab Ltd - 2021-05-01

FORM 4/A Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Du Ying 2. Issuer Name and Ticker or Trading Symbol Zai Lab Ltd [ ZLAB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chairwoman & CEO (Last) (First) (Middle) C/O ZAI LAB LIMITED, 4560 JINKE ROAD, BLDG 1, 4TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 05/01/2021 (Street) PUDONG, SHANGHAI, F4201210 4. If Amendment, Date Original Filed (MM/DD/YY) 05/04/2021 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Ordinary Shares 05/01/2021 M( 1 )( 2 ) 111,111 A $ 0.6 1,119,764 ( 1 ) D Ordinary Shares 1,008,653 ( 1 ) D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Options (Right to Buy) $ 0.6 05/01/2021 M( 1 )( 2 ) 111,111 ( 3 ) 10/22/2025 Ordinary Shares 111,111 $ 0 1,333,609 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Du Ying C/O ZAI LAB LIMITED 4560 JINKE ROAD, BLDG 1, 4TH FLOOR PUDONG, SHANGHAI, F4201210 X Chairwoman & CEO Signatures /s/ Bruce A. Blefeld, Attorney-in-Fact 06/02/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On May 4, 2021, the Reporting Person filed a Form 4 which inadvertently did not report that she exercised 111,111 Stock Options in connection with the sales of Ordinary Shares reported in such filing. However, as reported in this amendment, the Reporting Person exercised 111,111 Stock Options for Ordinary Shares, granted to her in connection with a stock option plan that fully vested on October 22, 2020. Accordingly, Table I, Column 5 is amended to reflect such acquisition of Ordinary Shares, pursuant to such exercise of Stock Options, giving effect to the various sale transactions previously reported on the initial filing of this Form 4. ( 2 )The reported transaction was effected pursuant to a sales plan adopted by the Reporting Person, dated March 3, 2021, expires December 31, 2021 and is intended to comply with Rule 10b5-1 under the Securities Exchange Act of 1931. ( 3 )The Stock Options fully vested as of October 22, 2020.

Remarks: The Power of Attorney given by Ms. Du was previously filed with the U.S. Securities and Exchange Commission on January 4, 2021 as an exhibit to the Form 3 filed by Ms. Du.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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