SCHEDULE: GeneDx Holdings: Casdin & Meister Group Reduces Stake

A group including Eli Casdin and Keith Meister reported a reduction in their beneficial ownership of GeneDx Holdings Corp. Class A common stock through an open market sale.

Summary

• Amendment No. 9 to Schedule 13D was filed by a group of reporting persons, including Eli Casdin and Keith Meister, regarding their holdings in GeneDx Holdings Corp. (formerly Sema4 Holdings Corp.).
• The reporting group disposed of 500,000 shares of Class A common stock on August 22, 2025, in an open market transaction.
• The shares were sold at a price of $120.9039 per share, totaling approximately $60,451,950.
• Following the transaction, Eli Casdin beneficially owns 3,599,671 shares, representing 12.4% of the outstanding Class A common stock.
• Keith A. Meister beneficially owns 3,630,826 shares, representing 12.5% of the outstanding Class A common stock.
• Casdin Capital, LLC and Casdin Partners Master Fund, L.P. beneficially own 3,007,164 shares, representing 10.5% of the outstanding Class A common stock.
• Corvex Management LP beneficially owns 3,058,629 shares, representing 10.6% of the outstanding Class A common stock.
• The beneficial ownership percentages are based on 28,726,248 shares of Class A common stock outstanding as of July 24, 2025, as reported in the Issuer's Form 10-Q filed on July 29, 2025.
• Eli Casdin's holdings include 35,975 shares with sole voting/dispositive power and 3,563,696 shares with shared voting/dispositive power, including shares from warrants, vested options, and restricted stock units.
• Keith Meister's holdings include 34,912 shares with sole voting/dispositive power and 3,595,914 shares with shared voting/dispositive power, including shares from warrants, vested options, and restricted stock units.
• Private placement warrants held by CMLS Holdings LLC (controlled by Casdin and Meister) are exercisable at $379.50 per share.

Sentiment

Score: 4

Explanation: The sale of a significant block of shares by a major shareholder group, including board members, typically indicates a less positive outlook or a decision to realize gains, which can be viewed negatively by the market.

Negatives

• A significant shareholder group, including board members Eli Casdin and Keith Meister, reduced their stake in GeneDx Holdings Corp. by selling 500,000 shares.

Future Outlook

NA

Industry Context

NA

Related Party Transactions

• A group of reporting persons, including board members Eli Casdin and Keith Meister, disposed of 500,000 shares of Class A common stock in an open market transaction.

Stakeholder Impact

• Shareholders may perceive the sale by a significant investor group, including board members, as a negative signal, potentially leading to downward pressure on the stock price.

Key Dates

Recommendation

The sale of a substantial block of shares by a significant investor group, including board members, typically signals a less optimistic outlook or a move to realize profits. This action could exert downward pressure on the stock. However, without additional fundamental analysis or explicit reasons for the sale, a 'hold' recommendation is prudent to observe market reaction and company performance.

Keywords

GeneDx Holdings Corp., GDX, Schedule 13D, Beneficial Ownership, Insider Selling, Casdin Capital, Corvex Management, Eli Casdin, Keith Meister, Class A Common Stock, SEC Filing