Stocks drifted in light volume Wednesday, ending little changed, as investors remained cautious.
Comcast's stock hit the highest since 1999 before closing up 2.98 percent at $40.13, and GE gained 3.59 percent to $23.39.
The S&P 500 is up 6.6 percent so far this year, partly due to stronger-than-expected corporate earnings and a better economic outlook.
The S&P is about 3 percent away from closing at a record high. It has gained 12 percent in the first three months of 2012.
A scarcity of sellers after a consistent string of gains is a positive sign and shows the uptrend is intact, said King Lip, chief investment officer at Baker Avenue Asset Management in San Francisco.
The Dow Jones industrial average fell 35.79 points to 13,982.91. The S&P rose 0.06 percent to 1,520.33, and the Nasdaq composite index was up 0.33 percent, to 3,196.88.
According to Thomson Reuters data, of the 364 companies in the S&P 500 that have reported results, 70.3 percent have exceeded analysts' expectations, above a 62 percent average since 1994. -- Reuters