Wall Street opens lower on Europe concerns

Dow Jones, S&P 500 index and Nasdaq down 1% each

U.S. stocks opened lower on Thursday as investors were skeptical that the latest European Union summit would agree on concrete measures to tackle the region's debt crisis.

Financial shares were the weakest, falling 1.2% after a report that JPMorgan Chase's trading loss could be as big as $9 billion.

The Dow Jones industrial average was down 99.68 points, or 0.79 percent, at 12,527.33. The Standard & Poor's 500 Index was down 11.15 points, or 0.84%, at 1,320.70. The Nasdaq Composite Index was down 34.17 points, or 1.19 percent, at 2,841.15.