X0508 4 2024-01-02 false 0001590877 REGENXBIO Inc. RGNX 0001700659 PAKOLA STEVE C/O REGENXBIO INC. 9804 MEDICAL CENTER DRIVE ROCKVILLE MD 20850 false true false false Chief Medical Officer true Common Stock 2024-01-02 4 F false 10385.00 17.95 D 92378.00 D Common Stock 2024-01-02 4 A false 32051.00 0.00 A 124429.00 D Common Stock 2024-01-03 4 S false 17237.00 17.3922 D 107192.00 D Stock Options (Right to buy) 18.34 2024-01-02 4 A false 50875.00 0.00 A 2034-01-02 Common Stock 50875.00 50875.00 D Represents shares of common stock withheld to pay taxes upon the vesting of restricted stock units originally granted to the reporting person on January 4, 2021, January 3, 2022 and January 3, 2023. The number of shares withheld was determined on January 2, 2024 based on the closing price of the issuer's common stock on December 29, 2023. Represents shares of common stock underlying a time-based restricted stock unit award (RSU). 25% of the shares subject to this RSU will vest on each of January 1, 2025, January 1, 2026, January 1, 2027 and January 1, 2028 while the recipient provides continuous service to the Issuer. This transaction was effected pursuant to a Rule 10b5-1 trading plan. This transaction was executed in multiple trades at prices ranging from $17.05 to $17.61. 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. 25% of the shares subject to this option shall vest after 12 months of continuous service with the Issuer. The balance will vest in equal monthly installments over the 36 months following January 2, 2025 while the optionee provides continuous service to the Issuer. /s/ Patrick J. Christmas as attorney-in-fact 2024-01-04