U.S. stock index futures fell on Thursday as an earnings forecast from retail giant Wal-Mart Stores Inc sowed doubt about consumer spending for the rest of 2009, threatening to end a six-session rally for the Dow.

Wal-Mart shares dipped 0.9 percent to $54.49 in premarket trading after the world's largest retailer reported a higher quarterly profit but forecast earnings for the current period that could miss current Wall Street estimates.

The headline numbers for Wal-Mart look OK, but the outlook is still vague at this point ... Investors need a more clear forward-looking picture, said Arthur Hogan, chief market analyst at Jefferies & Co in Boston.

S&P 500 futures dipped 6.1 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 44 points, and Nasdaq 100 futures shed 10 points.

Department store operator Kohl's Corp reported a larger-than-expected quarterly profit, helped by inventory controls and sales of brands it offers exclusively.

Investors are also closely eyeing weekly claims for jobless benefits due at 8:30 a.m. EST.

Other macroeconomic indicators include the U.S. federal budget for October at 2 p.m. EST. The federal deficit is expected to hit $150 billion for the first month in the new budget year, headed toward another $1 trillion-plus tide of red ink.

Stocks to watch include network equipment maker 3Com Corp , which soared more than 30 percent in extended trading on Wednesday after Hewlett-Packard Co agreed to buy 3Com for $2.7 billion.

Walt Disney Co and Nordstrom Inc are also due to report results later on Thursday.

(Editing by Padraic Cassidy)