U.S. Stocks Open Lower Amid Greece Worries

U.S. stocks opened slightly lower on Friday but the main indexes were on track to finish the week marginally higher. Investors turned cautious as concerns over Greece's debt-default drama lingered. The S&P 500 opened 7 points, or 0.3%, lower at 2,101. The Dow Jones Industrial Average dropped 54 points, or 0.3%, to 17,985. The Nasdaq Composite began the day lower, shedding 15 points, or 0.3% to 5,067.