X0508 4 2026-02-13 0 0001022079 QUEST DIAGNOSTICS INC DGX 0001520897 Doherty Catherine T. 500 PLAZA DRIVE SECAUCUS NJ 07094 0 1 0 0 EVP, Regional Businesses 1 Common Stock 2026-02-13 4 M 0 26165 112.17 A 94233 D Common Stock 2026-02-13 4 S 0 10573 205.2072 D 83660 D Common Stock 2026-02-13 4 S 0 10122 206.3706 D 73538 D Common Stock 2026-02-13 4 S 0 3500 207.0822 D 70038 D Common Stock 2026-02-13 4 S 0 1619 208.2107 D 68419 D Common Stock 2026-02-13 4 S 0 351 209.1024 D 68068 D Common Stock 4503 I 401(k)/SDCP Non-Qualifed Stock Option (right to buy) 112.17 2026-02-13 4 M 0 26165 112.17 D 2030-02-18 Common Stock 26165 0 D This exercise and sale reported were effected pursuant to a Rule 10b5-1 sales plan adopted by the reporting person. This transaction was executed in multiple trades at prices ranging from $204.745 to $205.740. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $205.770 to $206.7489. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $206.770 to $207.675. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $207.810 to $208.600. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $208.970 to $209.355. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. These underlying shares were acquired on a periodic basis by the trustee of the Company's tax qualified Profit Sharing (401(k)) and/or Supplemental Deferred Compensation Plan. The information was obtained from the plan administrator as of a current date. The number of shares is based on the account balance of the Company stock fund under each Plan (which includes some money market instruments) divided by the market price of the Company's stock as of that date. The options vested in three equal annual installments beginning on the first annual anniversary of the grant date. Sean D. Mersten, Attorney in Fact for Catherine T. Doherty 2026-02-17