X0508 4 2026-01-02 0 0001453687 Cartesian Therapeutics, Inc. RNAC 0002000122 Singer Michael C/O CARTESIAN THERAPEUTICS, INC. 7495 NEW HORIZON WAY FREDERICK MD 21703 1 0 0 0 0 Common Stock 2026-01-02 4 A 0 2600 0 A 56133 D Common Stock 383796 I by trust Common Stock 56719 I by trust Common Stock 7127 I by trust Common Stock 14788 I by spouse Common Stock 96219 I as custodian Common Stock 96219 I as custodian Stock Option (Right to Buy) 6.76 2026-01-02 4 A 0 7800 0 A 2027-01-02 2036-01-01 Common Stock 7800 7800 D Each Restricted Stock Unit represents a contingent right to receive one share of common stock, which will vest in full on January 2, 2027. Shares are held in a trust for the benefit of the reporting person's spouse and children. The reporting person's spouse is a trustee of the trust. Shares are held in a trust for which the reporting person is a beneficiary. The reporting person is a trustee of the trust. Shares are held in a trust for which the reporting person is a beneficiary. The reporting person's spouse is a trustee of the trust. Shares are held by the reporting person's spouse. The shares are held for LS, the child of the reporting person, through a custodial account established pursuant to the Uniform Transfer to Minors Act ("UTMA") for which the reporting person serves as custodian. The shares are held for SS, the child of the reporting person, through a custodial account established pursuant to the UTMA for which the reporting person serves as custodian. /s/ Matthew Bartholomae, Attorney-in-Fact for Michael Singer 2026-01-06