The Standard & Poor's 500 index traded above 1,500 for the first time since December 2007 following a sudden drop in claims for unemployment benefits, another sign that the labor market is healing.
A plunge in Apple's stock pulled the Nasdaq composite index lower. The electronics giant predicted slower sales.
The Dow Jones industrial average was up 84 points at 13,863 shortly before midday Thursday.
The Standard & Poor's 500 index rose five points to 1,500. The S&P has risen over the previous six days. The Nasdaq fell three points to 3,149.
The Labor Department reported that the number of Americans applying for unemployment aid fell last week to the lowest since January 2008.
Netflix soared 39 percent after surprising the market with strong subscriber growth and a profit.