Summary: U.S. markets open higher on the back of gains in Europe an Asia overnight. Hewlett-Packard topped forecasts and says it is gaining on rival IBM. Groupon beat estimates, but warned of rising acquisition and marketing costs. Priceline delivered quarterly results which were better than what Wall Street was expecting, but guidance for the current quarter is short of forecasts. Also, TheStreet's Jim Cramer is watching shares of Tesla, saying he would not bet against the electric car maker. TheStreet's Ruben Ramirez has details from the Nasdaq MarketSite.
