Three of the smallest sectors in the S&P 500 delivered the index's strongest performance in January, while the two largest sectors weighed on returns. The broad market index gained modest ground last month, with the State Street SPDR S&P 500 ETF Trust (SPY) up 0.6%, according to ETF Database. Beneath that muted headline number, though, sector performance told a much different story. The $32.7 billion State Street Energy Select Sector SPDR ETF (XLE) jumped 14.4% in January, leading all sectors despite energy ...