SALT LAKE CITY–(BUSINESS WIRE)–Sinclair Oil (Sinclair), an HF Sinclair (NYSE: DINO) brand, announced today the national launch of Mammoth Monday™, a new weekly fuel savings event designed to reward loyal customers with one of Sinclair’s biggest fuel discounts of the week. Beginning Monday, Aug. 3, 2026, eligible DINOPAY® users can activate an exclusive in-app coupon and save 20 cents per gallon—or 25 cents per gallon with Mobile Advantage™—every Monday at participating Sinclair stations. Avai