Energy stocks have gone from worst to first — and may even extend gains in the months ahead. The S&P 500 Index of the largest U.S. stocks dropped 11.1% (with dividends reinvested) in August’s mini-crash from the close of trading Aug. 17 through Aug. 25. Since then, the benchmark has come roaring back, gaining 13.1% from the close on Aug. 25 through Monday. FactSetThe S&P 500 Index was up 4% this year through Monday’s close, a decent showing considering August’s pain.