NEW YORK - The S&P 500 and the Nasdaq reached new record closing highs on Monday as optimism over potential medical advances in the war against the coronavirus pandemic pushed all three major U.S. stock indexes higher. The benchmark S&P 500 reclaimed its February closing high last week, confirming a bull market and the fastest recovery from a bear market trough on record. The blue-chip Dow, while leading Monday’s gains, remains nearly 4.2% below its all-time high, and down 0.8% year-to-date. The Nasdaq and the S&P have gained 26.8% and 6.2%, respectively, since the final closing bell of 2019. Of note, the Dow Transports index, often considered a barometer of U.S. economic health, handily outperformed the broader market. “There’s been a broadening in this rally and that’s what’s reflected in the transports,” said Chuck Carlson, chief executive officer at Horizon Investment Services in Hammond, Indiana. “ volume is accompanying this expanding breadth, and those are all bulli