X0306 4 2021-01-04 false 0001590877 REGENXBIO Inc. RGNX 0001652824 Mills Kenneth T. C/O REGENXBIO INC. 9600 BLACKWELL ROAD, SUITE 210 ROCKVILLE MD 20850 true true false false President and CEO Common Stock 2021-01-04 4 A false 40984.00 0.00 A 281984.00 D Stock Option (Right to Buy) 44.97 2021-01-04 4 A false 185167.00 0.00 A 2031-01-04 Common Stock 185167.00 185167.00 D 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, 2022, January 1, 2023, January 1, 2024 and January 1, 2025 while the recipient provides continuous service to the Issuer. 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 4, 2022 while the optionee provides continuous service to the Issuer. /s/ Patrick J. Christmas as attorney-in-fact 2021-01-06