X0306 4 2021-02-02 false 0001590877 REGENXBIO Inc. RGNX 0001521123 Christmas Patrick J. C/O REGENXBIO INC. 9600 BLACKWELL ROAD, SUITE 210 ROCKVILLE MD 20850 false true false false Chief Legal Officer Common Stock 2021-02-02 4 M false 10000.00 12.10 A 26372.00 D Common Stock 2021-02-02 4 S false 9500.00 44.77 D 16872.00 D Common Stock 2021-02-02 4 S false 500.00 45.13 D 16372.00 D Employee Stock Option (Right to Buy) 12.10 2021-02-02 4 M false 10000.00 0.00 D 2026-08-17 Common Stock 10000.00 12431.00 D This transaction was effected pursuant to a Rule 10b5-1 trading plan. This transaction was executed in multiple trades at prices ranging from $44.095 to $45.09. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $45.13 to $45.14. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. The previously granted option, representing a right to purchase a total of 125,000 shares, became exercisable as follows: 25% of the shares subject to this option vested on August 18, 2017, and the balance vested in equal monthly installments over the 36 months thereafter. /s/ Patrick J. Christmas 2021-02-04