SM Energy looks for energy (mainly natural gas) across the continental US. While the oil and gas exploration and production company spreads its operations across the US (the Gulf Coast, the Williston Basin in North Dakota and Montana, and the Permian Basin in West Texas and New Mexico, the Eagle Ford shale in South Texas, and the Haynesville Shale play in East Texas) it gets most of its revenues from South Texas and the Gulf Coast. In 2015 the company posted estimated proved reserves of 471.3 million barrels of oil equivalent, 14% down on 2014, as the result of the sale of its Mid-Continent assets.