GeneDx Holdings Corp.

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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Stamford, Connecticut

Dear Stockholder of GeneDx Holdings Corp.:

You are cordially invited to attend the 2026 annual meeting of stockholders (the “Annual Meeting”) of GeneDx Holdings Corp. (“we,” “us”, “our”, “GeneDx” or the “Company”) to be held via a virtual meeting on June 18, 2026 at 9:00 a.m. Eastern Time. You will be able to participate in the Annual Meeting and vote during the meeting via live webcast by visitingwww.virtualshareholdermeeting.com/wgs2026. We believe that a virtual stockholder meeting provides greater access to those who may want to attend, and therefore we have chosen this over an in-person meeting. It is important that you retain a copy of the control number found on the proxy card or voting instruction form, as such number will be required in order for stockholders to gain access to the Annual Meeting.

The Company is holding the Annual Meeting to:

(1) Elect one Class II director to serve until the 2029 annual meeting of stockholders and until her successor has been elected and qualified;

(2) Ratify the appointment of Ernst & Young LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026;

(3) Approve, on a non-binding advisory basis, the compensation of our named executive officers as disclosed in the accompanying proxy statement;

(4) Indicate, on a non-binding advisory basis, whether future advisory votes on the compensation paid by us to our named executive officers should be held every one, two, or three years; and

(5) Transact any other business that may properly come before the Annual Meeting or any adjournments or postponements thereof.

Each of these proposals is more fully described in the accompanying proxy statement, which each stockholder is encouraged to carefully read.

Your vote is very important. Whether or not you plan to attend the Annual Meeting, you are encouraged to submit your proxy and voting instructions via the Internet, by telephone or, if you received a paper copy of the meeting materials by mail, by completing, signing and dating the enclosed proxy card as promptly as possible and returning it in the enclosed envelope (to which no postage need be affixed if mailed in the United States). Even if you have given your proxy, you may still vote during the Annual Meeting by visitingwww.virtualshareholdermeeting.com/wgs2026 with your 16-digit control number assigned by Continental Stock Transfer & Trust Company included on your proxy card or obtained from them via email. Please note, however, that if your shares are held of record by a broker, bank or other nominee and you wish to vote at the Annual Meeting, you must obtain from the record holder a proxy issued in your name. You may revoke a previously delivered proxy at any time prior to the Annual Meeting. You may do so automatically by voting online during the Annual Meeting, or by delivering to us a written notice of revocation or a duly executed proxy bearing a date later than the date of the proxy being revoked.

On behalf of our Board, I would like to thank you for your support of GeneDx Holdings Corp.

The accompanying Notice of Annual Meeting and proxy statement are dated April 30, 2026 and are expected to be first distributed and made available on the Internet to the Company’s stockholders on or about April 30, 2026.

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To the Stockholders of GeneDx Holdings Corp.:

NOTICE IS HEREBY GIVEN that the annual meeting of the stockholders (the “Annual Meeting”) of GeneDx Holdings Corp., a Delaware corporation (“we,” “us”, “our”, “GeneDx” or the “Company”), is to be held via a virtual meeting on June 18, 2026 at 9:00 a.m. Eastern Time.

Stockholders or their proxyholders will be able to attend and vote at the Annual Meeting online by visitingwww.virtualshareholdermeeting.com/wgs2026 and using a control number assigned by Continental Stock Transfer & Trust Company. To receive access to the Annual Meeting, registered stockholders and beneficial stockholders (those holding shares through a stock brokerage account or by a bank or other nominee) will need to follow the instructions applicable to them provided in the accompanying proxy statement.

We are holding the Annual Meeting for the following purposes:

1. Proposal No. 1 - The Class II Director Election Proposal- To elect one Class II director of the Company to serve a three-year term expiring at the Company’s 2029 annual meeting of stockholders and until such director’s successor is duly elected and qualified (“Proposal No. 1”);

2. Proposal No. 2 - The Auditor Ratification Proposal- To ratify the appointment of Ernst & Young LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026 (“Proposal No. 2”);

3. Proposal No. 3 - Non-Binding Advisory Vote on Executive Compensation of our Named Executive Officers- To approve, on a non-binding advisory basis, the compensation of our named executive officers as disclosed in the accompanying proxy statement (“Proposal No. 3”);

4. Proposal No. 4 -Non-Binding Advisory Vote on the Frequency of Future Advisory Votes on the Compensation of our Named Executive Officers - To indicate, on a non-binding advisory basis, whether future advisory votes on the compensation paid by us to our named executive officers should be held every one, two, or three years (“Proposal No. 4”); and

To transact such other business as may properly come before the Annual Meeting or any adjournment or postponement thereof.

These items of business are more fully described in the accompanying proxy statement. We have not received notice of any other matters that may be properly presented at our Annual Meeting.

The record date for the Annual Meeting is April 20, 2026. Only stockholders of record at the close of business on the record date may vote at the Annual Meeting or any adjournment thereof. A complete list of our stockholders of record entitled to vote at the Annual Meeting will be available for ten days before the Annual Meeting at our principal executive offices for inspection by stockholders during ordinary business hours for any purpose germane to the Annual Meeting.

A majority of the voting power of all outstanding shares of capital stock of the Company entitled to vote must be present in person or by proxy to constitute a quorum for the transaction of business at the Annual Meeting. The Board recommends that you vote “FOR” Proposals 1 – 3 and “ONE YEAR” for Proposal 4.

TABLE OF CONTENTS

PROXY STATEMENT FOR THE ANNUAL MEETING OF STOCKHOLDERS TO BE HELD ON

JUNE 18, 2026

EXPLANATORY NOTES

Unless otherwise stated in this proxy statement or the context otherwise requires, references to:

•“GeneDx Holdings” refer to GeneDx Holdings Corp., a Delaware corporation;

•“Legacy GeneDx” refer to GeneDx, LLC, a Delaware limited liability company, which we acquired on April 29, 2022 (the “Acquisition”);

•“Legacy Sema4” refer to Sema4 OpCo Inc., a Delaware corporation, which consummated the business combination with CM Life Sciences, Inc. (“CMLS”) on July 22, 2021 (the “Business Combination”);

•“Fabric Genomics” refer to Fabric Genomics, Inc., a Delaware corporation, which we acquired on May 5, 2025 (the “Merger”); and

•“we,” “us” and “our,” the “Company” and “GeneDx” refer, as the context requires, to GeneDx Holdings and its consolidated subsidiaries.

In addition, unless otherwise stated in this proxy statement, all share amounts, exercise prices and other amounts set forth herein have been adjusted for the impact of a 1-for-33 reverse stock split of our Class A common stock, par value $0.0001 per share (“Class A Common Stock”), that became effective on May 4, 2023 (the “Reverse Stock Split”).