The stock market opened weaker Tuesday as investors hoped Apple (AAPL) and Microsoft (MSFT) will inject cheer into earnings season again. SPDR Dow Jones (DIA), the $12.6 billion ETF tracking a select basket of industry leaders, slipped 1%, with IBM (IBM) and United Technologies (UTX) among the biggest decliners. Both of these top 10 holdings of DIA sold off hard in late morning trading, on the heels of downbeat reports yesterday.