NEW YORK (Reuters) - Stocks dipped at the open on Tuesday, hobbled by "fiscal cliff" concerns as an upcoming debate in Congress over solving the nation's budget problems kept investors from making aggressive bets.

The Dow Jones industrial average <.DJI> dropped 65.58 points, or 0.51 percent, to 12,749.50. The Standard & Poor's 500 Index <.SPX> lost 7.92 points, or 0.57 percent, to 1,372.11. The Nasdaq Composite Index <.IXIC> fell 26.35 points, or 0.91 percent, to 2,877.91. (Reporting by Chuck Mikolajczak; Editing by James Dalgleish)