X0306 4 2018-09-17 false 0001590877 REGENXBIO Inc. RGNX 0001652827 Vasista Vittal C/O REGENXBIO INC. 9600 BLACKWELL ROAD, SUITE 210 ROCKVILLE MD 20850 false true false false Chief Financial Officer Common Stock 2018-09-17 4 S false 1561.00 70.43 D 120722.00 D Common Stock 2018-09-17 4 S false 200.00 72.03 D 120522.00 D Common Stock 2018-09-17 4 S false 1200.00 73.40 D 119322.00 D Common Stock 2018-09-17 4 S false 710.00 74.02 D 118612.00 D Common Stock 2018-09-17 4 S false 700.00 75.59 D 117912.00 D Common Stock 2018-09-17 4 S false 1479.00 76.79 D 116433.00 D Common Stock 2018-09-17 4 S false 600.00 77.87 D 115833.00 D Common Stock 2018-09-17 4 S false 450.00 78.64 D 115383.00 D Common Stock 2018-09-17 4 S false 500.00 79.63 D 114883.00 D Common Stock 2018-09-17 4 S false 100.00 80.80 D 114783.00 D Common Stock 2018-09-17 4 M false 30000.00 0.85 A 144783.00 D Employee Stock Option (Right to Buy) 0.85 2018-09-17 4 M false 30000.00 0.00 D 2024-09-23 Common Stock 30000.00 204900.00 D This transaction was effected pursuant to a Rule 10b5-1 trading plan. This transaction was executed in multiple trades at prices ranging from $79.40 to $80.00. 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 424,900 shares, became exercisable as follows: 284,683 of the shares subject to the option are initial shares ("Initial Shares") and 140,217 of the shares subject to the option are contingent shares ("Contingent Shares"). 72,235 of the Initial Shares vested on September 17, 2014, 53,112 of the Initial Shares vested on September 17, 2015 and an additional 4,426 of the Initial Shares vested upon each month of continuous service to the Company thereafter. 25% of the Contingent Shares were deemed vested as of September 17, 2014 on January 13, 2015 due to a subsequent event. The remainder of the Contingent Shares vested over four years of service following September 17, 2014, with 25% of the remaining 75% of Contingent Shares having vested on September 17, 2015 and the remaining Contingent Shares having vested in 36 equal monthly installments thereafter. (Continued from footnote 11) Notwithstanding the foregoing, 59,533 shares subject to this option that would have otherwise vested monthly between January 2018 and September 2018 were deemed vested as of December 31, 2015 on January 28, 2016 due to subsequent events. This transaction was executed in multiple trades at prices ranging from $70.05 to $70.85. 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 $71.55 to $72.50. 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 $72.80 to $73.75. 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 $73.85 to $74.35. 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 $75.00 to $75.90. 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 $76.35 to $77.25. 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 $77.40 to $78.15. 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 $78.40 to $78.95. 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. /s/ Patrick J. Christmas as attorney-in-fact 2018-09-19