Markets opened the week on a cautious note as the S&P 500 and Dow posted slight gains while the Russell 2000 lagged. Volatility spiked ahead of key Fed minutes, and investors rotated into defensive sectors like healthcare. UnitedHealth surged over 8%, lifting the Dow, while energy and small-cap names faced pressure. Options volume was heavy in SPY and QQQ, and gold and copper gained as the dollar weakened.