TransMedics Group, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

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TRANSMEDICS GROUP, INC.

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Message To Our Shareholders

TransMedics was founded with the mission to expand the utilization of available donor organs for transplantation while delivering the best possible clinical outcomes for our transplant patients. Today, our transformative OCSTM technology, comprehensive NOPTM clinical services, and integrated transplant logistics network have already fundamentally reshaped organ transplantation in the U.S. and we are expanding our operations to Europe and around the world – and we are just getting started.

Dear Fellow Shareholders:

2025 was another defining year for TransMedics. Our team completed over 5,100 U.S. OCS transplants, driving $605.5 million in total revenue, representing 37% year-over-year growth. We expanded OCS penetration in liver to 36% and heart to 18%, received full FDA IDE approval to initiate our ENHANCE heart and DENOVO lung clinical programs, and took our first steps in Europe with the launch of the first integrated organ transplantation network in Italy. Critically, for the third consecutive year, OCS was the engine of growth for the entire U.S. transplant market. As of 2025, overall U.S. liver, heart, and lung volumes are up 25% since 2022, a trend that would not have been possible without TransMedics. These results reflect the strength of our platform, our team, and our business model. We believe this foundation positions TransMedics to achieve even more success for our patients and for our shareholders.

Financially, 2025 marked our first full year of positive cash flow, generating $152 million for the year, a significant milestone that reflects our transition to a self-funding growth model. We also expanded operating margins to 18% in 2025, up from 8.5% in 2024, demonstrating operating leverage as revenue scales alongside disciplined cost management. These results give us the financial foundation to accelerate investment in our pipeline, our infrastructure, and our global expansion without compromising our path to sustained profitability.

We enter 2026 with significant momentum and a clear growth roadmap. Our ENHANCE Heart and DENOVO Lung programs are actively launching and are designed to further expand utilization of both DBD and DCD donors, growing overall heart and resurrecting the lung transplant markets. We are also investing in our disruptive OCS Generation 3.0 starting with our OCS Kidney platform, which we expect to catalyze growth well beyond our 10,000 U.S. NOP transplant goal in 2028 toward 20,000 cases by 2030. In parallel, we are developing our Gen-3.0 platform for liver, heart and lung, upgrading our existing systems to accelerate clinical adoption and scale while achieving better leverage on our product margins. Outside the U.S., we are actively expanding into Europe, beginning with the launch of our NOP program in Italy. European expansion has the potential to nearly double our transplant addressable market, and Italy is the first step in capturing that opportunity. Finally, we are exploring how TransMedics can play a more integrated national role in the U.S. transplant modernization initiative to maximize donor organ utilization at a national level.

The impact of our work is measurable in lives saved and transplants performed, but we remain driven by the opportunities in front of us. Tens of thousands of patients remain on transplant waiting lists in the U.S. alone, and we believe TransMedics is uniquely positioned to close that gap. To our shareholders: thank you for your continued trust and support our mission. To our clinical partners and our team: your commitment to patients is the foundation of everything we have built. We look forward to 2026 with confidence, and we remain deeply grateful for the opportunity to lead this work.

Sincerely,

Waleed Hassanein, M.D.

Founder, President and Chief Executive Officer

Notice of Annual Meeting of Shareholders

Purposes of the Meeting

Voting

Whether you plan to attend the Annual Meeting or not, it is important that you cast your vote by remote communication at the Annual Meeting or by proxy. You may vote over the Internet, telephone or by mail. You are urged to vote in accordance with the instructions set forth in the Proxy Statement. We encourage you to vote by proxy so that your shares will be represented and voted at the Annual Meeting, whether or not you can attend. You will need the 16-digit control number included with the Notice, on your proxy card, or the instructions that accompany your proxy materials to attend the Annual Meeting.

Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting

Under Securities and Exchange Commission rules that allow companies to furnish proxy materials to shareholders over the Internet, we have elected to make our proxy materials available to all of our shareholders over the Internet. We will be able to provide shareholders with the information they need, while at the same time conserving natural resources and lowering the cost of delivery. On or about April 10, 2026, we will commence sending the Notice of Internet Availability of Proxy Materials (the “Notice”) to all shareholders entitled to vote at the Annual Meeting. The Notice also provides instructions on how to vote online or vote by phone and includes instructions on how to receive a paper copy of the proxy materials by mail.

The accompanying Proxy Statement and our 2025 Annual Report on Form 10-K for the fiscal year ended December 31, 2025, which includes our audited financial statements, are also available for viewing, printing and downloading athttp://investors.transmedics.com/ under the Investors/Financial Information page and athttp://www.proxyvote.com.

By Order of the Board of Directors

Matthew Forsyth

Senior Vice President, General Counsel and Corporate Secretary

Andover, MA

April 10, 2026