Stocks rallied at the open on Friday, shrugging off a credit rating downgrade of Spain, led by optimism the euro zone will continue to make progress toward a solution to its debt crisis.

Strong results at Google Inc and a better-than-expected read on retail sales also added to the market's positive tone.

The Dow Jones industrial average <.DJI> was up 105.51 points, or 0.92 percent, at 11,583.64. The Standard & Poor's 500 Index <.SPX> was up 15.25 points, or 1.27 percent, at 1,218.91. The Nasdaq Composite Index <.IXIC> was up 37.10 points, or 1.42 percent, at 2,657.34.

(Reporting by Ryan Vlastelica; Editing by Padraic Cassidy)