U.S. stocks surged to their best day since last spring as doubt swung back to hope on Wall Street about a possible end to the war with Iran. The S&P 500 leaped 2.9% Tuesday for its largest gain since May. Just a day before, worries about the war had sent the main measure of Wall Street’s health more than 9% below its all-time high set early this year. The Dow Jones Industrial Average soared 1,125 points, or 2.5%, and the Nasdaq composite rallied 3.8%. Stocks strengthened after oil prices eased, which also sent yields lower in the bond market.