Best Buy Co BBY.N gained 1% after it raised its full-year comparable sales forecast. By Medha Singh and Shashank Nayar May 27 (Reuters) - Wall Street's main indexes rose on Thursday, helped by gains in industrial and financial shares, after data showing fewer-than-expected weekly jobless claims bolstered hopes of a speedy U.S. recovery. Worries about rising inflation and a potential tightening of policy have weighed on Wall Street's main indexes in May, with the benchmark S&P 500 .SPX on track for its smallest monthly gain in four.