Stocks open higher on Tuesday, boosted by financials, after Citigroup
* Geithner, FDIC chief's comments add to positive tone
* The Dow Jones industrial average <.DJI> gained 118.60 points, or 1.81 percent, to 6,665.65. The Standard & Poor's 500 Index <.SPX> added 15.14 points, or 2.24 percent, to 691.67. The Nasdaq Composite Index <.IXIC> rose 25.34 points, or 2.00 percent, to 1,293.98.
(Reporting by Rodrigo Campos; Editing by James Dalgleish)