X0609 4 2026-05-07 0 0001818331 GeneDx Holdings Corp. WGS 0001534261 Casdin Capital, LLC false 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK NY 10019 1 0 1 0 0001534264 Casdin Eli false 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK NY 10019 1 0 1 0 0001534265 Casdin Partners Master Fund, L.P. false 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK NY 10019 1 0 1 0 0001534260 Casdin Partners GP, LLC false 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK NY 10019 1 0 1 0 0 Cash Settled Swap 2026-05-07 4 P 1 500000 A Class A Common Stock 500000 500000 I See Footnote Cash Settled Swap 2026-05-08 4 P 1 300000 A Class A Common Stock 300000 800000 I See Footnote Cash Settled Swap 2026-05-11 4 P 1 50000 A Class A Common Stock 50000 850000 I See Footnote Casdin Partners Master Fund, L.P. (the "Master Fund") has entered into certain cash-settled swap agreements (the "Swap Agreements"), which represent economic exposure to an aggregate of 500,000 notional shares of the Issuer's Class A Common Stock, at a price of $38.1543 per share. The Swap Agreements provide the Master Fund with economic results that are comparable to the economic results of ownership but do not provide it with the power to vote or direct the voting or dispose of or direct the disposition of the securities that are referenced by the Swap Agreements. The Swap Agreements 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. The Master Fund has entered into certain cash-settled swap agreements (the "Swap Agreements"), which represent economic exposure to an aggregate of 300,000 notional shares of the Issuer's Class A Common Stock, at a price of $41.0261 per share. The Swap Agreements provide the Master Fund with economic results that are comparable to the economic results of ownership but do not provide it with the power to vote or direct the voting or dispose of or direct the disposition of the securities that are referenced by the Swap Agreements. The Master Fund has entered into certain cash-settled swap agreements (the "Swap Agreements"), which represent economic exposure to an aggregate of 50,000 notional shares of the Issuer's Class A Common Stock, at a price of $39.6602 per share. The Swap Agreements provide the Master Fund with economic results that are comparable to the economic results of ownership but do not provide it with the power to vote or direct the voting or dispose of or direct the disposition of the securities that are referenced by the Swap Agreements. 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. Casdin Capital LLC, By: /s/ Eli Casdin, Managing Member 2026-05-11 /s/ Eli Casdin, Eli Casdin 2026-05-11 Casdin Partners Master Fund, LP, By: Casdin Partners GP, LLC, its General Partner, By: /s/ Eli Casdin, Managing Member 2026-05-11 Casdin Partners GP LLC, By: /s/ Eli Casdin, Managing Member, /s/ Eli Casdin, Eli Casdin 2026-05-11