as bon pisani reports right now, that's working for the market. >> stocks again hit historic highs today. one of the reasons the market has remained strong is that there's been considerable rotation among sectors in the last year. the market leaders fall back, and they're usually replaced by market laggards. it happened again today. what sectors have lagged the market this year? energy stocks and bank stocks. what led today? energy stocks and bank stocks. energy was particularly dominant. oil was again back near $50. saudi arabia and russia announced yet another extension to their agreement to cut back supply. now extended it through the first quarter of 2018. big oil stocks all traded up on that news today. now, stocks had been strong because risk has been lower recently. earnings guidance, for example, for the year has been strong. that's good news. the global economy is improving. that's good news. the geopolitical risk is much lower thanks to france. also good news. now, the traders had been complaining about the low volatility. but that's historically not a problem for markets. trad