The chief executive of Wal-Mart Stores Inc. said he expects the US economy to remain extraordinarily challenging in the first half of the year and that he was not expecting a quick turnaround.

Lee Scott made the comments at the National Retail Federation’s annual conference being held in New York. He described it as his last public speech as head of the world’s largest retailer before retiring on Feb. 1.

Scott said the US government’s efforts to stimulate the economy should have “some impact,” but added: “I don’t see anything that tells me it’s going to turn around quickly.”