[Form 4] Zai Lab Limited American Insider Trading Activity

Rhea-AI Filing Summary

Du Ying, Chairperson & CEO and a director of Zai Lab Ltd (ZLAB), reported insider transactions dated 08/29/2025. The filing shows an acquisition of 604,376 American Depositary Shares (ADSs) at a price of $1.20 per ADS, increasing reported beneficial ownership to 1,141,338 ADSs. The filing also records a disposition of 251,319 ADSs at $32.59 per ADS, leaving 890,019 ADSs reported as beneficially owned after the transactions. The Form 4 discloses that each ADS represents ten ordinary shares and that the stock options underlying the reported acquisition fully vested on March 9, 2021. The form is signed by an attorney-in-fact on behalf of the reporting person on 09/03/2025.

Insights

Securities Analyst

TL;DR: Significant insider option exercise and a large sale occurred on the same date, changing reported ADS holdings materially.

The filing documents a simultaneous acquisition and disposition of ADSs by the CEO/director via option-related activity and open-market sale. The acquisition of 604,376 ADSs at $1.20 appears tied to stock options that vested earlier, while a sale of 251,319 ADSs at $32.59 reduced the post-transaction holding to 890,019 ADSs. For investors, the filing is a clear disclosure of insider liquidity and option exercise mechanics; it does not include additional context such as purpose of sale or use of proceeds.

Corporate Governance Expert

TL;DR: Routine Section 16 disclosure showing option exercise and a contemporaneous sale, properly reported on Form 4.

The report identifies the reporting person as both CEO and Chairperson and indicates transactions were reported timely on Form 4 with attorney-in-fact signature. The filing notes ADS fungibility and confirms the relevant options were fully vested as of March 9, 2021. The disclosure adheres to required reporting format and provides the core facts investors and compliance officers need to track insider activity.

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Du Ying

(Last) (First) (Middle)

C/O ZAI LAB LIMITED

314 MAIN STREET, 4TH FLOOR, SUITE 100

(Street)

CAMBRIDGE MA 02142

(City) (State) (Zip)

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)
	Chairperson & CEO

3. Date of Earliest Transaction (Month/Day/Year)
08/29/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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
American Depositary Shares(1)	08/29/2025		M		604,376	A	$1.2	1,141,338	D
American Depositary Shares(1)	08/29/2025		F		251,319	D	$32.59	890,019	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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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)	$1.2	08/29/2025		M			604,376	(2)	03/09/2026	American Depositary Shares(1)	604,376	$0	0	D

Explanation of Responses:

1. 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.

2. The Stock Options fully vested as of March 9, 2021.

	/s/ Bruce Blefeld, Attorney-in-Fact	09/03/2025
	** Signature of Reporting Person	Date
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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.