Signs of more corporate dealmaking sent U.S. stocks higher on Tuesday, allowing investors to take their mind off Greece's debt troubles.
Investors were also looking ahead to Wednesday's economic and interest rate policy update from the Federal Reserve.
They'll be looking for hints as to when the central bank will begin raising its key interest rate after holding it close to zero for more than six years.
Many economists expect the central bank will raise its rate in September if the economy keeps strengthening.
Ultra-low rates have helped drive the six-year bull market. Stocks have managed only small gains this year, as investors have obsessed about the outlook for interest rates.
The Dow Jones industrial average gained 113.31 points, or 0.6 percent, to 17,904.48. The Standard & Poor's 500 index rose 11.86 points, or 0.6 percent, to 2,096.29. The Nasdaq composite rose 25.58 points, or 0.5 percent, to 5,055.55.
All 10 sectors in the S&P 500 index moved higher, with consumer staples leading the gains. The sector rose 1.1 percent, but remains down 1.4 percent this year.