S&P 500 touches all-time high as earnings drive stock gains

The S&P 500 index briefly traded at an all-time high Tuesday just as the U.S. stock market's bull run came closer to becoming the longest on record.

The market's benchmark index eked out a slight gain, closing a little below the high mark it set in January. The rally pushed the Russell 2000 index of smaller-company stocks to a record high.

The current bull market, which began in 2009, is on track to become the longest in history on Wednesday, surpassing the bull run of the 1990s.

Tuesday's gains were driven by strong earnings by homebuilders, retailers and other companies.

"That we got to these levels in January was a big surprise, more so than we're back there now," said Bob Doll, chief equity strategist at Nuveen Asset Management.