Southwestern Energy Company, also called Southwestern Energy, is a holding company, which engages in the exploration, development, and production of natural gas, oil, and natural gas liquids (NGLs). It operates through the Exploration and Production (E&P); and Marketing segments. Read More The E&P segment includes operations in northeast Pennsylvania, West Virginia, and southwest Pennsylvania, The Marketing segment deals in the marketing and transportation of natural gas, oil and NGLs primarily produced in E&P. The company was founded on July 2, 1929 and is headquartered in Spring, TX. The listed name for SWN is Southwestern Energy Company.