* Yum shares fall on shrinkage of sales in China
* Monsanto stock jumps after strong earnings, raised outlook
* Sears says CEO to step down, shares rise
* Futures off: Dow 20 pts, S&P 2.5 pts, Nasdaq 1 pt
NEW YORK, Jan 8 (Reuters) - U.S. stocks were set to tick lower at the open on Tuesday as an earnings season expected to show sluggish corporate growth gets under way.
Profits in the fourth quarter are seen above the previous quarter's lackluster results, but analysts' current estimates are down sharply from where they were in October. Quarterly earnings are expected to grow by 2.8 percent, according to Thomson Reuters data.
German data showed industrial orders fell more than forecast in November due to a sharp drop in demand from abroad, reinforcing concerns that Europe's largest economy may have contracted in the fourth quarter of 2012.
"I'm surprised futures are holding up, given the relative disappointment that German data showed, but I think all eyes are on the beginning of earnings season," said Kim Forrest, senior equity research analyst at Fort Pitt Capital Group in Pittsburgh.
Monsanto Co shares rose 4 percent to $99.81 in premarket trading after the world's largest seed company raised its earnings outlook for fiscal 2013 and posted strong first-quarter results.
Education provider Apollo Group and Dow component Alcoa Inc, the largest U.S. aluminum producer, round out the start of earnings season after the closing bell.
"Alcoa is not a huge bellwether," Fort Pitt Capital's Forrest said, adding investors are focused more on companies' performance than on macroeconomic factors, so "we should be kind of flat until we get some company-oriented news."
S&P 500 futures were off 2.5 points and below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures were off 20 points and Nasdaq 100 futures dropped 1 point.
Shares of restaurant-chain operator Yum Brands Inc fell 4.3 percent to $65 a day after the KFC parent warned sales in China, its largest market, shrank more than expected in the fourth quarter.
London-traded Vodafone shares rose almost 3 percent after its partner in U.S. joint venture Verizon Wireless said it would be "feasible" to buy out the British group. U.S.-traded Vodafone stock dipped 0.8 percent.
Sears Holdings shares rose 2.5 percent to $44 in premarket trading a day after the company said its chief executive will step down for family health reasons. The U.S. retailer also reported a 1.8 percent decline in quarter-to-date sales at stores open at least a year.
GameStop shares fell 8.1 percent to $22.75 before the open after it reported sales for the holiday season and cut its guidance.
ConAgra Foods Inc priced a public offering of 8.1 million common shares at $29.75 per share, the foodmaker said on Monday. ConAgra closed at $30.17 during regular Monday trading.