Sec Form 4 Filing - Casdin Capital, LLC @ GeneDx Holdings Corp. - 2024-08-01

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Casdin Capital, LLC 2. Issuer Name and Ticker or Trading Symbol GeneDx Holdings Corp. [ WGS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 1350 AVENUE OF THE AMERICAS, SUITE 2600 3. Date of Earliest Transaction (MM/DD/YY) 08/01/2024 (Street) NEW YORK, NY10019 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Stock 08/01/2024 J( 1 ) 413,655 A $ 32.25 3,507,164 D ( 2 ) Class A Common Stock 3,142 D ( 3 ) Class A Common Stock 19,247 I See footnote ( 4 ) Class A Common Stock 333,144 I See footnote ( 5 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Casdin Capital, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Casdin Partners Master Fund, L.P. 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Casdin Partners GP, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Casdin Eli 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Signatures Casdin Capital LLC, By: /s/ Eli Casdin, Managing Member 08/05/2024 Signature of Reporting Person Date Casdin Partners Master Fund, LP, By: Casdin Partners GP, LLC, its General Partner, By: /s/ Eli Casdin, Managing Member 08/05/2024 Signature of Reporting Person Date Casdin Partners GP LLC, By: /s/ Eli Casdin, Managing Member, /s/ Eli Casdin, Eli Casdin 08/05/2024 Signature of Reporting Person Date /s/ Eli Casdin, Eli Casdin 08/05/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents a cross-trade, pursuant to which Casdin Partners FO1-MSV, LP ("Casdin FO1") transferred 413,655 shares of Class A Common Stock to Casdin Partners Master Fund, L.P. (the "Master Fund"). No reporting person has any pecuniary interest in Casdin FO1. ( 2 )The securities are owned directly by the Master Fund and may be deemed to be indirectly beneficially owned by (i) Casdin Capital, LLC, the investment adviser to the Master Fund ("Casdin"), (ii) Casdin Partners GP, LLC, the general partner of the Master Fund (the "GP"), and (iii) Eli Casdin, the managing member of Casdin and the GP. ( 3 )The securities are owned directly by Eli Casdin. ( 4 )The securities are owned directly by the GP and may be deemed to be indirectly beneficially owned by Eli Casdin, the managing member of the GP. ( 5 )The securities are owned directly by CMLS Holdings LLC ("CMLS Holdings"). The Board of Managers of CMLS Holdings includes Eli Casdin, who, as a member of the Board of Managers of CMLS Holdings, shares voting and investment discretion with respect to the common stock held by CMLS Holdings.

Remarks: Each Reporting Person disclaims beneficial ownership in the securities reported on this Form 4 except to the extent of its pecuniary interest, if any, therein, and this report shall not be deemed to be an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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