X0306 4 2019-01-03 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 Stock Option (Right to Buy) 40.82 2019-01-03 4 A false 190000.00 0.00 A 2029-01-03 Common Stock 190000.00 190000.00 D 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 3, 2020 while the optionee provides continuous service to the Issuer. /s/ Patrick J. Christmas as attorney-in-fact 2019-01-07