Pinterest Inc PINS.N jumped 11.90% after Piper Sandler upgraded the social media platform's stock to "overweight" from "neutral." The benchmark S&P 500 .SPX jumped as much as 2.76% to a three-month high early in the trading session on news that November U.S. consumer prices barely rose as gasoline and used cars cost less, leading to the smallest annual inflation increase in nearly a year at 7.1%. Still, equities pared gains ahead of the Fed's policy statement on Wednesday, in which the central bank is widely expected to announce a 50 basis point rate hike.