X0306 4 2018-11-16 false 0001590877 REGENXBIO Inc. RGNX 0001346164 Simpson Curran C/O REGENXBIO INC. 9600 BLACKWELL ROAD, SUITE 210 ROCKVILLE MD 20850 false true false false SVP, Technical Operations Common Stock 2018-11-16 4 M false 32882.00 22.00 A 72382.00 D Common Stock 2018-11-16 4 S false 4000.00 61.91 D 68382.00 D Common Stock 2018-11-16 4 S false 6883.00 62.79 D 61499.00 D Common Stock 2018-11-16 4 S false 6505.00 63.64 D 54994.00 D Common Stock 2018-11-16 4 S false 15494.00 64.71 D 39500.00 D Stock Option (Right to Buy) 22.00 2018-11-16 4 M false 32882.00 0.00 D 2025-08-30 Common Stock 32882.00 76101.00 D This transaction was effected pursuant to a Rule 10b5-1 trading plan. This transaction was executed in multiple trades at prices ranging from $61.21 to $62.18. 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 $62.25 to $63.20. 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 $63.27 to $64.255. 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 $64.30 to $65.16. 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 230,500 shares, became exercisable as follows: 25% of the shares subject to this option vested on August 31, 2016, and the balance vests in equal monthly installments over the 36 months thereafter while the optionee provides continuous service to the Issuer. /s/ Patrick J. Christmas as attorney-in-fact 2018-11-20