U.S. stocks opened slightly lower on Monday, with both the Dow and S&P 500 near records levels as investors digested an agreement by euro zone finance ministers to extend Greece's bailout by four months, provided it draws up a list of reforms.

The Dow Jones industrial average .DJI fell 9.6 points, or 0.05 percent, to 18,130.84, the S&P 500 .SPX lost 1.77 points, or 0.08 percent, to 2,108.53 and the Nasdaq Composite .IXIC dropped 3.25 points, or 0.07 percent, to 4,952.72.