Global shares down as euphoria over EU deal fades

US stocks ended lower on Monday, as concerns about Europe returned to the forefront after major credit ratings agencies warned that European leaders had not done enough to tackle the region's debt crisis.

The Dow Jones industrial average was down 161.81 points, or 1.33 percent, at 12,022.45. The Standard & Poor's 500 Index was down 18.62 points, or 1.48 percent, at 1,236.57. The Nasdaq Composite Index was down 34.59 points, or 1.31 percent, at 2,612.26.

European shares posted their biggest fall in three weeks as investors worried the measures outlined at last week's EU summit to strengthen budget discipline would be of only limited value in resolving the euro zone debt crisis.

The FTSEurofirst 300 index of top European shares fell 1.9 percent to close at 967.49 points, with trading volumes at just 76.2 percent of the index's 90-day average.

Banks and insurers were the biggest casualties, having had a strong run-up in the last two weeks on optimism the summit would offer a solution.

The STOXX Europe 600 Banking Index fell 3.9 percent, and has fallen 33.8 percent in 2011, making it the worst-performing sector, with several banks having suffered writedowns on euro zone peripheral debt.