Wall Street opens lower on Greece debt fears
Rating agency Moody's said it was reviewing Portugal's key rating for a possible downgrade.
The Dow Jones industrial average lost 89.79 points, or 0.82 percent, to 10,836.98. The Standard & Poor's 500 Index fell 12.88 points, or 1.10 percent, to 1,160.72. The Nasdaq Composite Index dropped 37.90 points, or 1.56 percent, to 2,386.35.
(Reporting by Rodrigo Campos)