Stocks are rising as investors pin their hopes on a key Federal Reserve meeting that could result in a decision to stimulate the economy.
Strong results from Carnival Corp. also suggest the upcoming earnings season could be better than expected.
The Fed began a two-day policy meeting Tuesday. On Wednesday, many analysts believe the central bank will announce new stimulus measures.
Carnival rose 6.7 percent, the most of any S&P 500 company, after the cruise operator said slimmer costs and strong ticket prices boosted its net income.
The Dow Jones industrial average is up 133 points, or 1.2 percent, at 11,532 in morning trading. The Standard & Poor's 500 index is up 15, or 1.2 percent, at 1,218. The Nasdaq composite is up 25, or 1 percent, at 2,638.