MaxCyte : 2022 Annual Report

MAXCYTE 2022 ANNUAL REPORT

Dear Stockholders,

This is the second annual report of MaxCyte, Inc. ("MaxCyte" or the "Company") following the listing of our common stock on the Nasdaq Global Select Market in July 2021.

Consistent with our annual report last year, this year's annual report consists of the Form 10-K that we filed with the U.S. Securities and Exchange Commission (the "SEC") on 15 March 2023 (enclosed), the proxy statement prepared in connection with our 2023 Annual Meeting of stockholders to be held on 22 June 2023 that we filed with the SEC on 28 April 2023 (enclosed) and certain additional information that we are including herein in accordance with the AIM Rules for Companies and in line with our prior practice for annual reports.

With over twenty years of clinical cell engineering expertise, MaxCyte's platform remains the premier cell engineering technology in our industry, enabling the development of a growing portfolio of advanced cell-based therapeutics. Leveraging that capability, our team delivered strong growth in 2022, our first full year as a Nasdaq listed company.

MaxCyte's performance in 2022 was driven by robust performance in our core cell engineering business, in both our key markets, cell therapy and drug discovery, as well as revenues by our partners' progress into and through clinical development. We expanded those partnerships in 2022 across diverse cell types, disease indications and geographic regions and now have a total of 20 product development partners including our most recent partnerships with Catamaran Bio, announced in January 2023, and Walking Fish, announced in May 2023. Our partners' programs continue to make exciting progress with several entering and/or progressing through the clinic. We continue to see a path towards a first commercially approved product enabled by our platform as Vertex's exa-cel program for Sickle Cell Disease and beta-thalassemia seeks regulatory approval. Overall, our global customer base is expanding across all stages of development and across a growing number of diseases. We now have more than 600 instruments placed with customers around the globe, as compared to just over 500 instruments at the end of 2021.

Additionally, our partnership pipeline remains robust as we continue into 2023. Our pipeline of new partners continues to expand not only in number but across the breadth of therapeutic modalities and indications including rare diseases, autoimmune, neurodegenerative, and solid tumors.

Much of the focus in 2022 was on investing in our people and capabilities at a measured but healthy rate. In 2022 we made important investments across multiple areas to support growing global end- markets and in preparation for our partners' progression through the clinic towards commercial product launch. These critical initiatives included investments in our field science, regulatory, quality assurance, applications development, engineering and supply teams as well as expansion of the sales, alliance support and marketing teams. We also invested in expanding our manufacturing capability and in product development during 2022, achieving notable milestones with the opening of our new headquarters in Rockville, Maryland, and the launch of our ExPERT VLx Large Scale Transfection System.

In 2023, we will continue to make investments to fuel MaxCyte's future success and financial growth, as well as support our customers' and partners' progress. These investments include growing our commercial teams, continuing expansion of our manufacturing capabilities including scaling our production capacity, enhancing our process development capabilities, and investing in ongoing product development. In addition, we continue to make investments in our applications lab to enable the rapidly growing market in next-generation cell therapies. We believe our targeted investments in 2022 and business momentum across our customer base position us well over the long-term.

Even with this confidence in our future progress, we continue to expect a more challenging operating environment in 2023 which will impact the timing of our customers' development projects and capital investments. However, we see these developments as short term in a therapeutic space with great promise over the long term. Importantly, we continue to have confidence in the value our enablement provides to our industry and in the strength of our SPL partnerships and pipeline opportunities. We have made critical strategic investments, positioning MaxCyte to execute on our long-term goals. We are

honored to support our partners, and believe we remain the partner of choice for non-viral cell engineering technology to support critical programs through development to commercialization. The cell and gene therapy industry is in the early innings of significant global opportunity to deliver therapies to patients and we remain very optimistic about the medium-to-longer term growth for MaxCyte.

Thank you for your continued support of MaxCyte.

Doug Doerfler

Chief Executive Officer

FOCUS ON ENVIRONMENTAL, SOCIAL AND GOVERNANCE RESPONSIBILITY

"At MaxCyte we remain committed to being good corporate citizens while supporting our customers who strive to develop breakthrough therapies to improve the lives of their patients," said Doug Doerfler, President and CEO of MaxCyte. "We recognize the importance of good environmental, social and governance ("ESG") and recently established Board-level oversight of the Company's ESG strategy and practices in addition to adopting the Quoted Companies Alliance Corporate Governance Code (the "QCA Code") to ensure MaxCyte continues to be managed in an efficient, effective, and entrepreneurial manner."

Our inaugural ESG Summary Report, published in May 2023, can be found on our website at:

https://investors.maxcyte.com/environmental-social-governance,and is included in this Annual Report.

DIRECTORS' REPORT

The Directors of the Company present their Report and audited Financial Statements for the year ended 31 December 2022.

Principal activity

MaxCyte (NASDAQ: MXCT; LSE: MXCT) is a leading cell-engineering company focused on providing enabling platform technologies to advance the discovery, development and commercialization of next- generation cell-based therapeutics and to support innovative, cell-based research. Over the past twenty years, the Company has developed and commercialised its proprietary Flow Electroporation platform, which facilitates complex engineering of a wide variety of cells.

Electroporation is a method of transfection, or the process of deliberately introducing molecules into cells, that involves applying an electric field in order to temporarily increase the permeability of the cell membrane. This precisely controlled increase in permeability allows the intracellular delivery of molecules, such as genetic material and proteins, that would not normally be able to cross the cell membrane as easily.

With increased knowledge of cell complexity and systems biology in the scientific community, researchers have sought to leverage or repurpose cell functions and/or machinery for research or therapeutic purposes. The ability to engineer living cells by introducing foreign molecules, such as gene editing systems and transgenes, has led to a revolution in biological research and resulted in numerous biological discoveries. Living human cells can also be engineered ex vivo, or outside the body, where they are repaired or reprogrammed to fight disease. In this case, the engineered cell itself is the drug.

Cell therapy has emerged as one of the fastest growing and most promising treatment modalities to address a host of human diseases. The recent success of multiple U.S. Food and Drug Administration

• "FDA") approved cell therapies providing long-lasting amelioration of symptoms or presence of disease has catalyzed tremendous investment-leading to exponential growth in cell-based therapies being evaluated for therapeutic applications. The Alliance for Regenerative Medicine ("ARM"), an international advocacy organization, estimates that the regenerative medicine sector, which consists of gene, cell, and tissue-based therapeutic developers, raised an aggregate of $12.6 billion in 2022 and that, as of January 2023, there were more than 2,220 active clinical trials focused on regenerative and advanced medicine, which includes gene therapy, cell-basedimmuno-oncology, cell therapy and tissue engineering.

Our ExPERT platform, which is based on our Flow Electroporation technology, has been designed to address this rapidly expanding cell therapy market and can be utilized across the continuum of the high- growth cell therapy sector, from discovery and development through commercialization of next- generation, cell-based medicines. The ExPERT family of products includes four instruments, which we call the ATx™, STx™, GTx™ and VLx™, as well as a portfolio of proprietary related disposables and consumables. We launched the ExPERT VLx™ instrument for very large-scale cell engineering in September 2022. Our disposables and consumables include PAs designed for use with our instruments,

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as well as accessories supporting PAs such as electroporation buffer solution and software protocols. We have garnered meaningful expertise in cell engineering via our internal research and development efforts as well as our customer-focused commercial approach, which includes a growing application scientist team. The platform is also supported by a robust intellectual property portfolio with more than 150 granted U.S. and foreign patents and more than 95 pending patent applications worldwide.

From leading commercial cell therapy drug developers and top biopharmaceutical companies to top academic and government research institutions, including the U.S. National Institutes of Health, the Company's customers have extensively validated the Company's technology. The Company believes the features and performance of its platform have led to sustained customer engagement. The Company's existing customer base ranges from large biopharmaceutical companies, including all of the top 10, and 20 of the top 25, pharmaceutical companies based on 2021 global revenue, to hundreds of biotechnology companies and academic centers focused on translational research.

Dividends

The Directors do not recommend the payment of a dividend currently.

Employee involvement

The Company's policy is to encourage employee involvement at all levels, as it believes that this is essential for the success of the business.

Directors

The Directors, as of the date of this report, are as follows:

Executive

• Doug Doerfler, President and Chief Executive Officer

Non-Executive

• Richard Douglas, PhD, Chairman
• Yasir Al-Wakeel
• Will Brooke
• Patrick Balthrop (appointed on 30 November 2022)
• Stan Erck
• Rekha Hemrajani
• John Johnston
• Art Mandell

Board Member	Board & Committee	Board &	Committee	Number of	External
	Meetings Held During	Meetings	Attended in	Corporate
	2022*	2022		Appointments	Held
				During 2022
Doug Doerfler	19		19	0
Richard Douglas	8		8	2
Yasir Al-Wakeel	11		11	0
Patrick Balthrop	1		1	1
Will Brooke	16		16	1
Stan Erck	13		13	1
Rekha Hemrajani	10		10	3
John Johnston	11		11	1
Art Mandell	14		14	0

Advisers

Nominated adviser and broker Panmure Gordon (UK) Limited, 40 Gracechurch Street London

EC3V 0BT

Joint Corporate Broker

Stifel Niolaus Europe Limited,

150 Cheapside, London EC2V 6ET

Auditors

CohnReznick LLP,

800 Towers Crescent Drive, Suite 1000,

Tysons, Virginia, U.S.A.

CohnReznick has expressed willingness to continue in office as auditor.

Registrars

Computershare Trust Company, N.A.

150 Royall Street

Canton, MA 02021

Counsel

Cooley (UK) LLP

22 Bishopsgate London EC2N 4BQ

Doug Doerfler

Executive Director, President and Chief Executive Officer

This report was approved by the Board on 19 June 2023.

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CORPORATE GOVERNANCE REPORT

Principles of good corporate governance

The Directors are committed to maintaining high standards of corporate governance and, as a company dual-listed on the Nasdaq Global Select Market in the United States and AIM in the UK, and as appropriate for a company located in the United States with its size and stage of development, MaxCyte adopts the QCA Code as set forth on www.maxcyte.com. The underlying principle of the QCA Code is that "the purpose of good corporate governance is to ensure that the company is managed in an efficient, effective and entrepreneurial manner for the benefit of all stockholders over the longer term." Our corporate governance is based on the leadership of our Board for the entire Company, and we believe it is essential to our ability to deliver our business strategy.

The Company has adopted an appropriate share dealing code in order to comply with Rule 21 of the AIM Rules for Companies (the "AIM Rules"), as well as U.S. securities laws, relating to Directors and applicable employees dealing in the Company's securities. The Company takes all reasonable steps to ensure compliance with such by its Directors and employees.

As the Company grows, it will regularly review the extent and appropriateness of its corporate governance practices and procedures.

As our business grows, the Company and Board are committed to managing our growth while focusing on environmental, social and governance ("ESG") issues. In April 2023, the Nominating & Corporate Governance Committee of the Board of Directors expanded its charter to include oversight of the Company's ESG strategy and practices. We developed our own ESG policy, part of which, as applicable and as practicable, focuses on meeting the UN's Sustainable Development Goals ("SDGs"). We currently have a number of existing policies in place which are linked to broader ESG and SDG policies, such as: Anti-Bribery and Corruption Policy; Standards of Conduct and Business Ethics; Conflicts of Interest, EEO and Anti- Harassment; and Employee Sick and Safe Leave. In particular, the Company has adopted the MaxCyte, Inc. Code of Conduct and Ethics, further details of which are set out on page 15 of the enclosed proxy statement.

Application of principles of the QCA Code

Board of Directors

The Board comprises eight Non-Executive Directors (including the Chairman) and one Executive Director. All of the Non-Executive Directors are considered to be independent for the purposes of the QCA Code.

All Directors receive regular and timely information about the Company's operational and financial performance. Formal Board meetings are scheduled throughout each financial year. A formal agenda and the accompanying Board papers are circulated in advance of each meeting.

All the Directors commit the time necessary to fulfil their roles at the Company.

The Board is responsible for overall Company strategy, acquisition and divestment policy, approval of the budget, approval of significant borrowing and major capital expenditure projects, and consideration of significant operational and financial matters. The Board monitors the exposure to key business risks and reviews the progress of the Company towards achievement of its strategic goals, budgets and forecasts. One of the Board's key functions is informed oversight of the Company's risk management process. In particular, the Board is responsible for monitoring and assessing strategic risk exposure, including a determination of the nature and level of risk appropriate for the Company. The Board oversees compliance with relevant legislation and regulations, including the AIM Rules, the UK Market Abuse Regulation and the QCA Code, as well as U.S. securities laws and Nasdaq rules. The Board also considers employee issues and key appointments. This is achieved by the close involvement of the Chief Executive Officer in the day-to-day running of the business and by regular reports submitted to and considered at meetings of the Board and its committees by the Chief Executive Officer and other executive officers.

In October 2021, the Board appointed Richard Douglas as its independent Chairman. Dr. Douglas has authority, among other things, to call and preside over Board meetings, including meetings of the independent directors, to set meeting agendas and to determine materials to be distributed to the Board. Accordingly, the Chairman has substantial ability to shape the work of the Board. The Company believes that separation of the positions of Chairman and Chief Executive Officer reinforces the independence of the Board in its oversight of the business and affairs of the Company. In addition, the Company believes that having an independent Chairman creates an environment that is more conducive to objective evaluation and oversight of management's performance, increasing management accountability and improving the ability of the Board to monitor whether management's actions are in the best interests of the Company and its stockholders. As a result, the Company believes that having an independent Chairman can enhance the effectiveness of the Board as a whole.

The Board receives training from the EVP, General Counsel, as required, in light of any changes to the law or best corporate governance. In particular, the Board receives regular training on the Company's obligations, and the individual responsibilities of each Director, under the UK Market Abuse Regulation.

The Board ensures it has appropriate expertise to meet the needs of the Company and the Board evaluates its performance on an ongoing basis.

Developing the Company's employees, in preparation for future advancement and making sure qualified employees are actively engaged by the Company, is a key focus of the Chief Executive Officer and other executive officers, with input from the Nominating and Corporate Governance Committee, Compensation Committee and the Board as a whole, as appropriate.

The Company's corporate governance is based on the leadership of our Board. The Chief Executive Officer and other executive officers regularly monitor the Company's cultural environment and seek to address any concerns that may arise.

The Board considers employee compensation, key appointments and other employee issues. This is achieved by the close involvement of the Chief Executive Officer and other executive officers in the day-to-day running of the business and by regular reporting at meetings of the Board and its committees.

The Board has an Audit Committee, a Compensation Committee and a Nominating and Corporate Governance Committee. Details of the composition and activities of the Audit Committee, the Compensation Committee and the Nominating and Corporate Governance Committee are found on pages 10 to 15 in the enclosed proxy statement.

All Directors are able to take independent professional advice in relation to their duties, as necessary, at the Company's expense. Each of the Board's committees has authority to engage legal counsel or other experts or consultants, as it deems appropriate to carry out its responsibilities. The Board evaluates its performance on an ongoing basis. The Board does not currently undertake a formal annual evaluation process, provided all Board members are required to complete annual questionnaires to ensure their independence and that they possess the qualifications to sever as Directors of the Company.

In July 2021, the Board documented the governance practices to be followed by the Company by adopting Corporate Governance Guidelines to assure that the Board will have the necessary authority and practices in place to review and evaluate the Company's business operations as needed and to make decisions that are independent of the Company's management. The guidelines are also intended to align the interests of directors and management with those of the Company's stockholders. The Corporate Governance Guidelines set forth the practices the Board intends to follow with respect to board composition and selection including diversity, board meetings and involvement of senior management, Chief Executive Officer performance evaluation, succession planning and board committees and compensation.

The Directors are divided into three classes, as nearly equal in number as possible, designated: Class I, Class II and Class III. The Class I Directors are Doug Doerfler, Yasir Al-Wakeel and Rekha Hemrajani, whose term expires at the 2025 Annual Meeting. The Class II directors are Art Mandell, Stan Erck and Patrick Balthrop, whose term expires at the 2023 Annual Meeting and will be nominated for election at

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that meeting for a three-year term expiring at the 2026 Annual Meeting. The Class III directors are Will Brooke, John Johnston and Richard Douglas, whose term expires at the 2024 Annual Meeting.

The role of the Chairman is to lead and oversee the Board, and to promote good corporate governance within the Company. The Chief Executive Officer has responsibility for the business operations, for implementing the Company's strategy and for the day-to-day running of the business.

Relationship with Stockholders

The Board attaches high importance to maintaining good relationships with all stockholders. The Chief Executive Officer and certain other executive officers hold regular meetings with institutional stockholders to keep them updated on the Company's performance, strategy, management and Board membership. The Chief Executive Officer and certain other executive officers give regular briefings to analysts who cover the industry and actively encourage more analysts to follow the Company.

Further, the Company holds an Annual Meeting for all stockholders to attend and encourages open discussion and dialogue. Beyond the Annual Meeting, the Chief Executive Officer meets regularly with investors to provide them with updates on the Company's business.

Details of the process by which stockholders may communicate with the Board or any of its directors are set out on page 15 of the enclosed proxy statement.

The Company has an investor relations team which can be contacted at [e-mail].

The Company values its communications with all its stakeholders. The Company's website is updated on a regular basis and users have the ability to view the description of the Company's business as well as its financial statements and other relevant information as such becomes available.

The Chief Executive Officer and certain other executive officers are in regular communication with stockholders to share information regarding the Company and to understand the views of stockholders which are communicated to the Board as appropriate.

On behalf of the Board

Richard Douglas, PhD

Chairman

19 June 2023

DIRECTORS' RESPONSIBILITIES

The Directors, in addition to being responsible for defining and overseeing the corporate governance of the Company in accordance with the QCA Code, are responsible for ensuring the Annual Report and the Financial Statements are prepared in accordance with applicable law and regulations.

The AIM Rules require the Directors to ensure the financial statements are prepared for each financial year. Under those rules, the financial statements are prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP").

The Directors believe that the accounts should not be approved unless the Directors are satisfied that the accounts give a true and fair view of the state of the Company's affairs and of the profit or loss of the Company for the period presented. In preparing financial statements, the Directors are required to:

• Properly select and apply accounting policies;
• Present information, including accounting policies, in a manner that provides relevant, reliable, comparable and understandable information; and
• Provide additional disclosures when compliance with the specific requirements in U.S. GAAP are insufficient to enable users to understand the impact of particular transactions, other events, and conditions on the Company's financial position and financial performance.

The Directors are responsible for ensuring the Company maintains adequate accounting records that are sufficient to show and explain the Company's transactions and disclose with reasonable accuracy at any time the financial position of the Company and enable them to ensure that the financial statements comply with U.S. GAAP and the AIM Rules. They are also responsible for safeguarding the assets of the Company and hence for taking reasonable steps for the prevention and detection of fraud and other irregularities.

The Directors are responsible for the maintenance and integrity of the corporate and financial information included on the Company's website. Legislation in the United Kingdom governing the preparation and dissemination of financial statements may differ from legislation in other jurisdictions.

The Directors confirm that to the best of their knowledge the financial statements, prepared in accordance with U.S. GAAP, give a true and fair view of the assets, liabilities, financial position and profit or loss of the Company.

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