US STOCKS-Wall St falls after China devaluation
* Commodities fall as cheaper yuan boosts dollar
* Materials shares lead decline; Apple drops
* Bond prices jump on China FX move, Fed rate speculation
* Indexes down: Dow 1.2 pct, S&P 1 pct, Nasdaq 1.3 pct (Updates to close)
By Caroline Valetkevitch
Aug 11 (Reuters) - U.S. stocks declined on Tuesday as China's surprise devaluation of the yuan currency hit companies with a big exposure to the country and added to worries about the global economic outlook.
Apple fell 5.2 percent to $113.54 in its biggest daily percentage decline since late January 2014, and the stock was the biggest drag on all three major indexes. Jefferies raised concerns about the demand for the iPhone, primarily in China.
Among other companies with a big exposure to China, Caterpillar was down 2.6 percent at $78.04. Yum Brands fell 4.9 percent to $83.54. General Motors shares fell 3.5 percent to $30.83, though it said the devaluation of the yuan would have a "limited and manageable" impact on its business.
The currency move by the world's top metals consumer pushed copper and aluminum to six-year lows, and the S&P materials index dropped 1.9 percent, leading sector declines for the S&P 500. Freeport-McMoRan dropped 12.3 percent to $10.22. Continuación...