Targa Resources gathers, processes and transports natural gas and natural gas liquids, operating pipelines and processing facilities concentrated heavily in the Permian Basin and other major U.S. shale regions. Natural gas liquids, byproducts of natural gas production like propane and butane, need to be separated and processed before they can be sold, and Targa's processing plants perform that function for producers who don't have their own processing infrastructure. Much of Targa's revenue comes from fee-based contracts tied to the volume of gas and liquids it processes and transports, giving it more stable, toll-road-like economics than a business directly exposed to commodity prices. The company's growth has been closely tied to shale drilling activity in the basins where it operates, since more drilling activity produces more natural gas and liquids that need gathering, processing and transportation.