U.S. stocks fell at the open on Tuesday as concerns over European banks outweighed a deal by Warren Buffett's Berkshire Hathaway to buy railroad company Burlington Northern.

The Dow Jones industrial average <.DJI> was down 79.58 points, or 0.81 percent, at 9,709.86. The Standard & Poor's 500 Index <.SPX> fell 8.45 points, or 0.81 percent, at 1,034.43. The Nasdaq Composite Index <.IXIC> slid 17.01 points, or 0.83 percent, at 2,032.19.

In its largest-ever acquisition, Berkshire Hathaway Inc will pay $26 billion for Burlington Northern Santa Fe Corp .

But the broader market was hit after Swiss lender UBS AG posted its fourth consecutive quarterly loss and Britain's Royal Bank of Scotland Plc and Lloyds Banking Group Plc agreed to sell hundreds of branches and key businesses to appease European Union concerns over state aid and competition.

(Reporting by Angela Moon, Editing by Jeffrey Benkoe)