Precisely where would you house the steel? Wesco Financial chooses Precision Steel Warehouse (PSW). The Wesco subsidiary is a steel service center, a sort of middle man that buys steel directly from manufacturers and then processes it to sell in smaller batches to other businesses. Products -- including carbon and alloy steels, stainless steels, aluminum, and brass -- are sold to a wide range of customers; PSW also offers services such as blanking, cut-to-length, edging, leveling, shearing, and slitting. The company operates from locations in Illinois and North Carolina. Wesco is primarily owned by Warren Buffett's Berkshire Hathaway.