X0609 4 2026-06-29 false 0001590877 REGENXBIO Inc. RGNX 0001700659 PAKOLA STEVE false C/O REGENXBIO INC. 9804 MEDICAL CENTER DRIVE ROCKVILLE MD 20850 false true false false Chief Medical Officer false Common Stock 2026-06-29 4 S false 19608.00 11.04 D 213009.00 D Common Stock 2026-07-01 4 M false 36725.00 7.86 A 249734.00 D Common Stock 2026-07-01 4 S false 36725.00 12.86 D 213009.00 D Stock Options (Right to Buy) 7.86 2026-07-01 4 M false 36725.00 0.00 D 2035-01-02 Common Stock 36725.00 66973.00 D This transaction was effected pursuant to a Rule 10b5-1 trading plan. This transaction was executed in multiple trades at prices ranging from $11.00 to $11.18. 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. The previously granted option, representing a right to purchase a total of 103,698 shares, became exercisable as follows: 25% of the shares subject to this option vested on January 2, 2026, 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 2026-07-01