Shares of U.S. Steel Corp. X, -3.31% fell more than 2% in the extended session Thursday after the steel producer reported sales slightly below expectations and swung to a GAAP profit. U.S. Steel said it earned $91 million, or 35 cents a share, in the quarter, versus a loss of $391 million, or $2.30 a share, in the year-ago quarter. Adjusted for one-time items, the company earned $1.08 a share. Sales rose to $3.66 billion, from $2.75 billion a year ago. Analysts polled by FactSet expected adjusted earnings of 88 cents a share on sales of $3.68 billion. The company benefited from a recent acquisition and heightened demand, it said. “A strong market and our disciplined approach to capital allocation position us well to translate earnings into cash flow,” Chief Executive David Burritt said in a statement. Shares of U.S. Steel ended the regular trading day down 3.3%.