LeonaBio (ATHA) counsel sells 1,328 shares to cover RSU tax bill

Rhea-AI Filing Summary

LeonaBio, Inc. executive Mark Worthington reported a mix of share transactions tied to vesting equity awards. On March 3, 2026, 5,726 restricted stock units were exercised into the same number of common shares at $0.00 per share, reflecting a standard RSU conversion.

On March 4, 2026, 1,328 common shares were sold in an open-market transaction at a weighted-average price of $5.37 per share to cover tax withholding obligations under LeonaBio’s mandatory “sell to cover” policies, which the filing notes was not a discretionary sale. After these transactions, Worthington directly held 18,376 common shares.

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

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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^*

Worthington Mark

(Last) (First) (Middle)

C/O LEONABIO, INC.

18706 NORTH CREEK PARKWAY, SUITE 104

(Street)

BOTHELL WA 98011

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
LeonaBio, Inc. [ LONA ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	GENERAL COUNSEL and CCO

3. Date of Earliest Transaction (Month/Day/Year)
03/03/2026

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
Common Stock	03/03/2026		M		5,726	A	$0	19,704	D
Common Stock	03/04/2026		S(1)		1,328	D	$5.37(2)	18,376	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
Restricted Stock Units	(3)	03/03/2026		M			5,726	(4)	(4)	Common Stock	5,726	$0	0	D

Explanation of Responses:

1. Represents shares of common stock sold to cover tax withholding and remittance obligations in connection with the vesting of restricted stock units ("RSU") pursuant to mandatory "sell to cover" policies maintained by the Issuer and provisions contained in the reporting person's applicable RSU agreement, and does not represent a discretionary sale by the reporting person. No additional shares of common stock were sold by the reporting person.

2. The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price, respectively, of shares sold. These shares were sold in multiple transactions at prices ranging from $5.03 to $5.70, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range set forth herein.

3. Each RSU represents a contingent right to receive one (1) share of Issuer's common stock.

4. On March 3, 2025, the reporting person was granted 5,726 RSUs (as adjusted for the 10-for-1 reverse stock split completed on September 17, 2025). 100% of the RSUs vested on the one (1) year anniversary of the grant date.

	/s/ Mark Worthington	03/05/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transactions did LeonaBio (ATHA) report for Mark Worthington?

LeonaBio reported that General Counsel and CCO Mark Worthington exercised 5,726 RSUs into common stock, then sold 1,328 shares in the market to cover tax withholding obligations. After these transactions, he directly held 18,376 shares of LeonaBio common stock.

Was the LeonaBio (ATHA) share sale by Mark Worthington discretionary?

The share sale was not discretionary. The filing explains that 1,328 shares were sold solely to satisfy tax withholding and remittance obligations under LeonaBio’s mandatory “sell to cover” policies and the RSU agreement, with no additional shares sold by Worthington.

How many LeonaBio (ATHA) RSUs vested for Mark Worthington and when?

Mark Worthington had 5,726 restricted stock units that vested in full on the one-year anniversary of a March 3, 2025 grant. Each RSU represented the right to receive one share of LeonaBio common stock, which converted into shares upon vesting.

What price range applied to the LeonaBio (ATHA) tax-related share sale?

The reported price is a weighted average, and the filing notes the 1,328 shares were sold in multiple transactions at prices ranging from $5.03 to $5.70 per share. The weighted-average sale price disclosed was $5.37 per share.

What is Mark Worthington’s role at LeonaBio (ATHA) in this Form 4?

In this Form 4, Mark Worthington is identified as an officer of LeonaBio serving as General Counsel and Chief Compliance Officer. The reported RSU vesting and related share sale reflect equity compensation arrangements associated with his executive role at the company.