The Dow Jones industrial average <.DJI> was up 62.44 points, or 0.53 percent, at 11,871.23. The Standard & Poor's 500 Index <.SPX> was up 8.33 points, or 0.67 percent, at 1,246.58. The Nasdaq Composite Index <.IXIC> was up 27.36 points, or 1.04 percent, at 2,664.82.
Among Nasdaq gainers, Apple Inc <AAPL.O> rose 1.6 percent to $399.38 and Oracle Corp <ORCL.O> added 1 percent to $32.44.
Markets opened higher as strong earnings from Caterpillar Inc <CAT.N> offset concerns European policymakers were struggling to narrow differences in tackling the region's debt crisis.
(Reporting by Ryan Vlastelica; editing by Jeffrey Benkoe)