X0508 4 2023-12-31 0 0001787297 Passage BIO, Inc. PASG 0001987062 Borthwick Kathleen ONE COMMERCE SQUARE 2005 MARKET STREET, 39TH FLOOR PHILADELPHIA PA 19103 0 1 0 0 SVP, Interim CFO 0 Common Stock 2023-12-31 4 M 0 30000 A 36608 D Common Stock 2024-01-02 4 S 0 10672 0.91 D 25936 D Restricted Stock Unit 2023-12-31 4 M 0 30000 0.00 D Common Stock 30000 0 D Restricted stock units ("RSUs") convert into common stock on a one-for-one basis. Includes 3,082 shares acquired on May 13, 2022 and 3,526 shares acquired on November 15, 2023 under the 2020 Employee Stock Purchase Plan. The sale reported on this Form 4 represents an Issuer mandated sale by the Reporting Person to satisfy tax withholding obligations in connection with the vesting and settlement of RSUs; it does not represent a discretionary trade by the Reporting Person. Pursuant to the Issuer's equity incentive plan, an award recipient's tax withholding obligations must be funded by a "sell to cover" transaction. Each RSU represents a contingent right to receive one share of Issuer's common stock. 100% of the total restricted stock units vested on December 31, 2023, subject to the Reporting Person's provision of service to the Issuer on each vesting date. /s/ Edgar Cale, Attorney-in-Fact 2024-01-03