U.S. stocks open higher on tech upgrades By: MarketWatch July 12, 2010 at 09:59 AM EDT U.S. stocks rise at the start of trading Monday as investors prepared cautiously for the start of second-quarter earnings and tech upgrades boosted the Nasdaq. Read More >> Related Stocks: Alcoa BP Plc ADR Dow Jones Industrial Average (EOD) Microsoft SanDisk Corp Standard & Poors 500 Yahoo