X0508 4 2025-10-22 0 0001022079 QUEST DIAGNOSTICS INC DGX 0001127304 PFEIFFER GARY M 500 PLAZA DRIVE SECAUCUS NJ 07094 1 0 0 0 0 Common Stock 2025-10-22 4 S 0 1482 182.40 D 29431 D Phantom Stock 2025-10-23 4 I 0 4413.284 190.58 D Common Stock 4413.284 0 D This transaction constitutes an intra-plan transfer in the Quest Diagnostics Incorporated Amended and Restated Deferred Compensation Plan for Directors from the company stock fund to another investment option. The phantom common stock units were payable in cash and represented a like number of shares of the company's common stock. The amount includes shares acquired via dividend reinvestment since the date of reporting person's last filing on Form 4 pursuant to the Amended and Restated Deferred Compensation Plan for Directors. Sean D. Mersten, Attorney in Fact for Gary M. Pfeiffer 2025-10-24