Enterprise Rent-A-Car, online at enterprise.com, save money on hot items when shopping on Enterprise Rent-A-Car when applying our coupons, promo codes during checkout. Trust us, these coupons are good. Make the best of our Enterprise Rent-A-Car promo codes to get 15% OFF. All discounts are totally free to use. Enterprise Holdings, Inc. is an American holding company headquartered in Clayton, Missouri. It is the parent company of car rental companies Enterprise Rent-A-Car, National Car Rental, Alamo Rent a Car, PhillyCarShare, and Enterprise CarShare. The holding company was formed in 2009 as a result of Enterprise Rent-A-Car's 2007 acquisition of Vanguard Automotive Group, the parent company of National Car Rental and Alamo Rent a Car. Enterprise ranks as the largest car rental company in the United States.