The United States Steel Corporation (NYSE: X), more commonly known as U.S. Steel, is an American integrated steel producer with major production operations in the United States, Canada, and Central Europe. The company was the world's 15th largest steel producer in 2014. It was renamed USX Corporation in 1986 and back to United States Steel Corporation in 2001 when the shareholders of USX spun off the oil & gas business of Marathon Oil and the steel business of U. S. Steel to shareholders.