[Form 4] REGENXBIO Inc. Insider Trading Activity

Rhea-AI Filing Summary

Craig Malzahn, Chief Technology Officer of REGENXBIO Inc. (RGNX), reported a non-derivative transaction dated 09/01/2025 in which 234 shares of common stock were disposed at a price of $8.93 per share. After the transaction he beneficially owned 17,585 shares directly. The filing states the 234 shares were withheld to pay taxes upon the vesting of restricted stock units originally granted on September 1, 2022, with the withholding amount calculated using the issuer's closing stock price on August 29, 2025. The form was signed via attorney-in-fact on 09/03/2025.

Insights

Securities/Insider Transactions Analyst

TL;DR: Routine tax-withholding sale following RSU vesting; no new purchases or change in control implied.

The Form 4 documents a common practice where shares underlying vested restricted stock units are withheld to satisfy tax obligations. The disposal of 234 shares at $8.93 appears solely for tax withholding rather than a market-sale intent. Post-transaction beneficial ownership remains 17,585 shares directly, indicating continued insider exposure but no material reduction in position size disclosed.

Corporate Governance Specialist

TL;DR: Administrative insider reporting consistent with Section 16 rules; disclosure is timely and specific.

The filing identifies the reporting person, relationship to the issuer (Chief Technology Officer and director), transaction date, and precise mechanics: shares withheld upon RSU vesting using a specified closing price. The signature via attorney-in-fact and the inclusion of the RSU grant date provide clear auditability for corporate records and regulatory compliance.

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
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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^*

Malzahn Craig

(Last) (First) (Middle)

C/O REGENXBIO INC.

9804 MEDICAL CENTER DRIVE

(Street)

ROCKVILLE MD 20850

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
REGENXBIO Inc. [ RGNX ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Technology Officer

3. Date of Earliest Transaction (Month/Day/Year)
09/01/2025

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
Common Stock	09/01/2025		F		234(1)	D	$8.93	17,585	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

Explanation of Responses:

1. Represents shares of common stock withheld to pay taxes upon the vesting of restricted stock units originally granted to the reporting person on September 1, 2022. The number of shares withheld was determined based on the closing price of the issuer's common stock on August 29, 2025.

Remarks:

	/s/ Patrick J. Christmas as 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.

FAQ

What transaction did Craig Malzahn (RGNX) report on Form 4?

The filing reports the disposition of 234 shares of REGENXBIO common stock on 09/01/2025 at $8.93 per share.

Why were the 234 shares disposed of according to the Form 4?

The filing states the 234 shares were withheld to pay taxes upon the vesting of restricted stock units granted on September 1, 2022.

How many REGENXBIO shares does Craig Malzahn beneficially own after the reported transaction?

After the transaction the reporting person beneficially owned 17,585 shares directly.

What price was used for the sale or withholding of shares in the Form 4?

The transaction price reported for the disposed shares is $8.93 per share, with the withholding amount determined using the closing price on August 29, 2025.

When was the Form 4 signed and by whom?

The signature was executed by Patrick J. Christmas as attorney-in-fact on 09/03/2025.