X0508 4 2026-02-18 0 0001022079 QUEST DIAGNOSTICS INC DGX 0001955217 KUPPUSAMY KARTHIK 500 PLAZA DRIVE C/O QUEST DIAGNOSTICS INC SECAUCUS NJ 07094 0 1 0 0 SVP, Clinical Solutions 0 Common Stock 2026-02-18 4 F 0 252 210.01 D 8173 D Common Stock 2026-02-18 4 F 0 259 206.99 D 7914 D Common Stock 2026-02-18 4 A 0 2135 0 A 10049 D Common Stock 2026-01-28 5 L 0 E 16 183.516 A 10065 D Common Stock 1655 I 401(k) Common Stock 358 I By Trust Non-Qualifed Stock Option (right to buy) 204.96 2026-02-18 4 A 0 9853 0 A 2036-02-18 Common Stock 9853 9853 D Disposition of common stock to the issuer solely to cover tax withholding obligations arising from the vesting of restricted stock units. Represents an award of restricted stock units. Reflects shares that were acquired pursuant to a dividend reinvestment plan administered by the reporting person's broker and eligible for deferred reporting on Form 5 under Rule 16a-6. The reporting person has chosen to report such transaction early on this Form 4. The amount includes exempt purchases made under the Company's stock purchase plan since the date of the reporting person's last filing on Form 4. These underlying shares were acquired on a periodic basis by the trustee of the Company's tax qualified Profit Sharing (401(k)) 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 the Plan (which includes some money market instruments) divided by the market price of the Company's stock as of that date. The options vest in three equal annual installments beginning on the first annual anniversary of the grant date. Sean D. Mersten, Attorney in Fact for Karthik Kuppusamy 2026-02-20