* NAHB homebuilder index on tap
* AMD shares drop as CFO to leave
* FedEx falls on results, outlook
* Futures down: Dow 12 pts, S&P 1.7 pts, Nasdaq 2.5 pts
By Edward Krudy
New York, Sept 18 (Reuters) - U.S. stock index futures retreated for a second day on Tuesday, suggesting stocks would continue to ease from multi-year highs as investors looked to upcoming economic data to help extend the central bank stimulus rally.
U.S. stocks have rallied 7 percent since early August, propelling the S&P 500 index to the highest in nearly five years on central bank stimulus in Europe and the United States. But analysts say that for the rally to continue economic data needs to improve.
"If we don't start seeing stronger U.S. economic data or we don't start seeing strong policy measures out of the Chinese, then I think we're going be due for a correction," said Jack de Gan, chief investment officer at Harbor Advisory Corp in Portsmouth, New Hampshire.
De Gan said if the economic data does not improve, he would look for a correction in the S&P 500 back towards the index's 50-day moving average, which is about 5 percent below current levels.
"There are reasons to believe these weak data in the U.S. could bottom shortly and begin to improve but it hasn't happened yet," he said. "The longer we go, the more stretched this little rally will be."
The NAHB Housing Market Index at 10 a.m. (1400 GMT) is expected to be little changed in September after unexpectedly gaining in the previous two months. However, at 37 on the index sentiment remains well below the 50s to 70s seen in the 1990s and 2000s.
FedEx Corp cut its profit forecast for its fiscal year 2013 on Tuesday, saying that a weakening world economy had prompted customers to shift toward lower-priced shipping. The shares fell 1.4 percent to $88.05. Earlier this month FedEx warned the slowing economy was hurting its results.
S&P 500 futures fell 1.7 points and were 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 fell 12 points, and Nasdaq 100 futures lost 2.50 points.
Advanced Micro Devices Inc shares fell 6.2 percent in premarket trade. The firm said Chief Financial Officer Thomas Seifert was leaving the struggling personal computer chipmaker to pursue other opportunities.
Weakness in commodity markets looked set to weigh on related stocks. Copper fell for a second day after a rally triggered last week by the U.S. Federal Reserve's new stimulus efforts ran out of steam and investors booked profits. Shares in Freeport McMoRan Copper & Gold fell 1 percent on light volume.
"The market may already have 'prepaid' for the QE3 easing announcement," said Goldman Sachs in a research note. "For the equity market moves to extend, an improvement in the macro data will now need to show up."
European shares and the euro fell on Tuesday as investors turned their attention from central bank stimulus to slowing global growth and uncertainty about Spain's desire for an international aid package.
Dole Food Company Inc will sell two businesses to Itochu Corp for $1.7 billion in cash - a deal that will help the world's largest fruit and vegetable producer pay down its heavy debt load while expanding Itochu's food presence in new markets such as China. Dole's shares jumped 9.5 percent in premarket trading.
Time Warner Cable Inc has put a process in motion to sell its stake in wireless service provider Clearwire Corp , according to a regulatory filing.
European car sales fell 8.5 percent in August for an 11th straight monthly decline, led by Ford, General Motors and Fiat and mid-market brands bore the brunt of the slump in markets including Italy, France and Germany.