KFC parent Yum Brands Inc posted a quarterly profit that failed to assuage investors worries about slowing growth in China, its most important market.

Shares in the fast-food chain, whose third-quarter profit matched Wall Street's expectations, fell 1.9 percent in extended trading.

China -- the world's fastest growing major economy -- is Yum's biggest earnings driver, accounting for just over 40 percent of overall profits.

Closely watched sales at Yum's established restaurants in China jumped 19 percent in the third quarter.

That increase came as higher wage and commodity costs caused the company's China restaurant margins to fall by 3.9 basis points to 21.3 percent.

Yum said on Tuesday it raised menu prices after the quarter ended to help offset higher costs.

Yum, based in Louisville, Kentucky, has almost 4,200 restaurants, mostly KFC outlets, in China. It is the largest Western restaurant brand in China, with far more restaurants than competitors such as McDonald's Corp and Starbucks Corp .

Sales at established restaurants in Yum Restaurants International (YRI) were up 3 percent during the third quarter. That division includes Yum's other non-U.S. markets such as France, India and Russia.

While Yum's business is robust in international markets, it is struggling at home.

Overall sales at U.S. restaurants open at least one year fell 3 percent. That result included declines of 2 percent at Taco Bell, 3 percent at Pizza Hut and 3 percent at KFC.

Operating profit was up in China and YRI, but down in the United States.

Yum's third-quarter net income rose to $383 million, or 80 cents per share, from $357 million, or 74 cents per share, a year earlier.

Excluding special items, Yum's profit was 83 cents per share, matching analysts' average estimate, according to Thomson Reuters I/B/E/S.

Revenue rose to $3.27 billion from $2.86 billion a year earlier.

Shares in Yum fell to $48.60 after closing at $49.44 on the New York Stock Exchange,

(Reporting by Lisa Baertlein; Editing by Richard Chang)