LeonaBio (ATHA) CEO converts 22,254 RSUs and sells shares for taxes

Rhea-AI Filing Summary

LeonaBio, Inc. President and CEO Mark James Litton reported several equity transactions involving company stock. On March 3, 2026, 22,254 restricted stock units were exercised at $0.00 per share, converting into the same number of common shares and bringing his direct common stock holdings to 63,082 shares.

On March 4, 2026, 5,156 common shares were sold at a weighted-average price of $5.37 per share to cover tax withholding obligations triggered by the RSU vesting under the company’s mandatory “sell to cover” policies; no additional shares were sold. After this tax-related sale, he directly owned 57,926 common shares. Separate irrevocable trusts established for his children each held 656 common shares as indirect ownership.

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^*

Litton Mark James

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	PRESIDENT and CEO

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		22,254	A	$0	63,082	D
Common Stock	03/04/2026		S(1)		5,156	D	$5.37(2)	57,926	D
Common Stock								656	I	By Irrevocable Trust of OSL(3)
Common Stock								656	I	By Irrevocable Trust of SWL(4)
Common Stock								656	I	By Irrevocable Trust of WGL(5)

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	(6)	03/03/2026		M			22,254	(7)	(7)	Common Stock	22,254	$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. Reflects Common Stock held by Irrevocable Trust of OSL held for the benefit of Dr. Litton's children.

4. Reflects Common Stock held by Irrevocable Trust of SWL held for the benefit of Dr. Litton's children.

5. Reflects Common Stock held by Irrevocable Trust of WGL held for the benefit of Dr. Litton's children.

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

7. On March 3, 2025, the reporting person was granted 22,254 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, Attorney-in-Fact on behalf of Mark James Litton	03/05/2026
	** Signature of Reporting Person	Date
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FAQ

What insider stock transactions did LeonaBio (ATHA) report for its CEO?

LeonaBio’s President and CEO Mark James Litton exercised 22,254 restricted stock units into common shares, then sold 5,156 shares. The sale was solely to cover tax withholding obligations from the RSU vesting under mandatory company policies, leaving him with 57,926 directly held shares.

How many LeonaBio (ATHA) RSUs vested and converted for the CEO?

22,254 LeonaBio restricted stock units vested and converted into the same number of common shares for CEO Mark James Litton. These RSUs were originally granted on March 3, 2025, and fully vested on the one-year anniversary of the grant, following the company’s equity award terms.

Why did the LeonaBio (ATHA) CEO sell 5,156 shares of common stock?

The 5,156 LeonaBio shares were sold to cover tax withholding and remittance obligations from RSU vesting under mandatory “sell to cover” policies. Footnotes specify this was not a discretionary sale and that no additional common shares were sold by the reporting person.

What are the LeonaBio (ATHA) CEO’s direct and indirect share holdings after these transactions?

After the RSU conversion and tax-related sale, CEO Mark James Litton directly held 57,926 LeonaBio common shares. In addition, three irrevocable trusts established for his children each held 656 common shares, reported as indirect ownership positions associated with the reporting person.

What do the irrevocable trusts holding LeonaBio (ATHA) shares represent?

The filing notes three irrevocable trusts—OSL, SWL, and WGL—each holding 656 LeonaBio common shares. Footnotes explain these trusts hold stock for the benefit of Dr. Litton’s children, and the positions are reported as indirect ownership linked to the reporting person.