Stocks extended losses on Monday as investors fretted over the banking sector's exposure to a possible sovereign default in Greece and its effect on European lenders.

The Dow Jones industrial average was down 111.48 points, or 1.02 percent, at 10,801.90. The Standard & Poor's 500 Index was down 14.40 points, or 1.27 percent, at 1,117.02. The Nasdaq Composite Index was down 38.40 points, or 1.59 percent, at 2,377.00.

Belgian-French bank Dexia's capital position looked increasingly stretched by its exposure to debt-laden Greece. The bank's board will hold a meeting later on Monday, a source said.

The S&P financial sector fell 2.5 percent.