The 1922 discovery of natural gas about 20 miles southeast of Rock Springs, Wyoming by a predecessor exploration and production company led to the creation of what is today Questar Market Resources, a wholly owned subsidiary of Questar Corporation and a subholding company that conducts its operations through several subsidiaries. Questar Exploration and Production Company acquires, explores for, develops and produces gas and oil in the Rocky Mountain and Mid-Continent regions. Wexpro Company manages, develops and produces cost-of-service reserves for affiliated utility, Questar Gas. Questar Gas Management Company provides gas-gathering and processing services for affiliates and third parties. Questar Energy Trading Company markets equity and third-party gas and oil, provides risk-management services, and through Clear Creek Storage Company, LLC, owns and operates an underground gas-storage reservoir.