U.S. stocks opened lower Monday as Greece ventures into an uncertain future when voters overwhelmingly rejected austerity plans aimed at relieving the nation's crushing debt. Sales of computer and mobile chips climbed 5% in May, according to the Semiconductor Industry Association. Tesla Motors (TSLA) shares are less than 4% from their all time high set on September 4th. Shares rallied 4% after the electric car maker reported record sales. Securities regulators have launched a broad investigation into whether hedge funds and other investors are improperly selling hot private technology stocks amid a boom in the trading of such shares, according to the Wall Street Journal.