Questar Corporation (Questar) is a natural gas-focused energy company with four major lines of business: gas and oil exploration and production, midstream field services, energy marketing, interstate gas transportation, and retail gas distribution. Its operations are conducted through its three principal subsidiaries. Questar Market Resources, Inc. is a sub holding company that operates through four principal subsidiaries: Questar Exploration and Production Company, which acquires, explores for, develops and produces natural gas, oil and NGL; Wexpro Company manages, develops and produces cost-of-service reserves for gas utility affiliate Questar Gas; Questar Gas Management Company that provides midstream field services including natural gas-gathering and processing services for affiliates and third parties, and Questar Energy Trading Company markets equity and third-party natural gas and oil, provides risk-management services and owns and operates an underground gas-storage reservoir.