X0508 4 2025-03-14 0001287098 MAXCYTE, INC. MXCT 0001375884 Swirsky Douglas J C/O MAXCYTE, INC. 9713 KEY WEST AVENUE, SUITE 400 ROCKVILLE MD 20850 true CHIEF FINANCIAL OFFICER false Common Stock 2025-03-14 4 A 0 37500 0 A 118750 D Employee Stock Option (right to buy) 3.29 2025-03-14 4 A 0 150000 0 A 2035-03-13 Common Stock 150000 150000 D These shares represent restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of the Issuer's Common Stock. Twenty-five percent (25%) of the RSUs shall vest on March 14, 2026, and the remainder shall vest in three (3) equal annual installments thereafter, subject to the Reporting Person's continued service to the Issuer through each vesting date. Twenty-five percent (25%) of the shares underlying this option shall vest on March 14, 2026, and the remainder shall vest in thirty-six (36) equal monthly installments thereafter, subject to the Reporting Person's continued service to the Issuer through each vesting date. /s/ Douglas J. Swirsky 2025-03-18