Uncertainty is weighing on Wall Street about a possible end to the war with Iran, and stock indexes are slipping as oil prices rise.
The S&P 500 fell 0.4% Thursday and gave back most of its gain from the day before.
The Dow Jones Industrial Average edged up by 42 points, and the Nasdaq composite sank 0.6%.
Stock markets fell more sharply in much of Asia and Europe.
They're the latest flip-flops in a week after Iran rejected a U.S. offer for a ceasefire.
Oil prices rose more than 3%, and Treasury yields climbed in the bond market.