REGENXBIO CTO has 234 shares withheld for taxes

REGENXBIO’s CTO had a small number of shares withheld to cover taxes from RSU vesting and continues to hold over eighty thousand shares.

Rhea-AI Filing Summary

REGENXBIO Inc. (RGNX) reported that Chief Technology Officer Craig Malzahn had 234 shares of common stock disposed of on September 1, 2026 to satisfy tax withholding obligations upon the vesting of previously granted restricted stock units. The shares were valued at $9.32 per share for this tax calculation, and Malzahn now directly holds 81,960 shares of REGENXBIO common stock.

Insider Trade Summary

Tax Withholding: 234 shares

Tax Withholding 1 txn

Insider Malzahn Craig

Role Chief Technology Officer

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock F1	234	$9.32	$2K

Holdings After Transaction: Common Stock — 81,960 shares (Direct)

Footnotes (1)

1. F1. 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 September 1, 2026.

Key Figures

Shares withheld for taxes: 234 shares Price per share for tax calculation: $9.32 per share Shares held after transaction: 81,960 shares +2 more

5 metrics

Shares withheld for taxes 234 shares Common stock withheld on September 1, 2026 to pay RSU vesting taxes

Price per share for tax calculation $9.32 per share Value used for the September 1, 2026 tax-withholding transaction

Shares held after transaction 81,960 shares Direct REGENXBIO common stock holdings of CTO after September 1, 2026 transaction

RSU original grant date September 1, 2022 Restricted stock units whose vesting triggered the tax withholding

Transaction date September 1, 2026 Date of tax-withholding disposition reported on Form 4

Key Terms

restricted stock units, withheld to pay taxes, closing price, payment of tax liability by delivering or withholding securities

4 terms

restricted stock units financial

"upon the vesting of restricted stock units originally granted"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

withheld to pay taxes financial

"Represents shares of common stock withheld to pay taxes"

closing price market

"determined based on the closing price of the issuer's common stock"

payment of tax liability by delivering or withholding securities financial

"transaction type is a payment of tax liability by delivering"

FAQ

What insider transaction did REGENXBIO (RGNX) disclose for its CTO?

REGENXBIO disclosed that CTO Craig Malzahn had 234 shares of common stock withheld on September 1, 2026 to pay taxes due on the vesting of restricted stock units originally granted on September 1, 2022.

Was the REGENXBIO (RGNX) insider transaction an open-market sale?

No. The Form 4 states the transaction was a payment of tax liability by delivering or withholding securities in connection with RSU vesting, not an open-market sale of shares by the CTO.

How many REGENXBIO (RGNX) shares does the CTO hold after this transaction?

Following the September 1, 2026 tax-withholding transaction, CTO Craig Malzahn directly holds 81,960 shares of REGENXBIO common stock, as reported in the Form 4 filing.

At what price were the REGENXBIO (RGNX) shares valued for the tax withholding?

The 234 shares withheld for taxes were valued at $9.32 per share, based on the filing’s stated price, which the footnote explains was determined using the closing price of REGENXBIO common stock on September 1, 2026.

Was the REGENXBIO (RGNX) CTO’s Form 4 transaction under a Rule 10b5-1 plan?

No. The Form 4 indicates the Rule 10b5-1 checkbox is not marked, and there is no footnote stating that the September 1, 2026 tax-withholding transaction was carried out under a Rule 10b5-1 trading plan.

What triggered the RSU-related tax withholding for REGENXBIO (RGNX)’s CTO?

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

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/03/2026 - 05:32 PM Accepted by SEC EDGAR 09/03/2026 - 05:30 PM Learn about SEC filing dates

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^*

Malzahn Craig

(Last) (First) (Middle)

C/O REGENXBIO INC.

9804 MEDICAL CENTER DRIVE

(Street)

ROCKVILLE MARYLAND 20850

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/01/2026

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

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

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

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	09/01/2026		F		234(1)	D	$9.32	81,960	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 September 1, 2026.

Remarks:

	/s/ Patrick J. Christmas as attorney-in-fact	09/03/2026
	** 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.
* Form 4: SEC 1474 (03-26)