MAXCYTE, INC.

Rule 10b5-1 Trading Plans

There were noadoptions orterminations of contracts, instructions or written plans for the purchase or sale of our securities by our Section 16 officers and directors for the three months ended September 30, 2025 intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act (“Rule 10b5-1 Plan”).

We inadvertently omitted the disclosure of a Rule 10b5-1 Plan adopted by Rekha Hemrajani, a director, on March 19, 2025, in Item 5 of Part II in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2025. The details of this plan are set forth below.

CFO Severance Agreement Amendment

On November 12, 2025, the Company entered into the CFO Severance Agreement Amendment with Douglas Swirsky, pursuant to which Mr. Swirsky will transition from his position as Chief Financial Officer of the Company, effective as of the Retention Date. Mr. Swirsky will continue to be eligible for bonus payments for fiscal year 2025 and the applicable portion of 2026; in addition, to support the retention of Mr. Swirsky through the Retention Date and in exchange for executing a separation and release agreement, he will be entitled to a one-time payment of $150,000, payable following the Retention Date. Following May 31, 2026, Mr. Swirsky will provide the company with consulting services for a period of eighteen consecutive months during which his equity awards will continue to vest in accordance with their terms based on his continued service and the Company will reimburse Mr. Swirsky for the cost of his COBRA benefits. Mr. Swirsky will be eligible to receive a monthly fee of $10,000 per month, payable in arrears, for services to the Company.