* Initial jobless claims on tap
* Costco same-store sales increase
* Futures off: Dow 31 pts, S&P 4.7 pts, Nasdaq 7 pts
By Chuck Mikolajczak
NEW YORK, May 5 (Reuters) - U.S. stock index futures edged lower on Thursday as commodities lost ground on growing worries about less demand after recent tepid economic data and ahead of Friday's key payrolls report.
* U.S. crude futures slumped 2.4 percent to $106.62 and ICE Brent futures shed 2.7 percent to $117.90, while silver was poised for its largest weekly fall in over 20 years. Mining company Freeport-McMoRan Copper and Gold Inc dipped 1.5 percent to $50.40 in premarket trade.
* Investors awaited weekly jobless claims, with economists in a Reuters survey forecasting a total of 410,000 new filings, compared with 429,000 in the prior week.
* Also coming are monthly retail sales, showing the extent of consumer spending. U.S. warehouse club operator Costco Wholesale Corp posted a better-than-expected 12 percent rise in April sales, helped by higher gasoline prices and strengthening foreign currencies.
* S&P 500 futures shed 4.7 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 dropped 31 points, and Nasdaq 100 futures lost 7 points.
* Whole Foods Market Inc's quarterly profit topped Wall Street's view and the grocer raised its full-year profit forecast.
* Electronic Arts Inc will be in the spotlight after the video game publisher said revenue rose and it raised its quarterly outlook, citing higher sales of games "Crysis 2" and "Dead Space 2."
* Investors awaited company results from Kraft Foods Inc, American International Group Inc and Visa Inc.
* Through Wednesday, with 386 of the S&P 500 companies having reported, 68 percent had profits that beat Wall Street expectations, according to Thomson Reuters data.
* European shares fell on Thursday, after weak earnings from companies including Lloyds Banking Group PLC and with investors cautious ahead of the latest European Central Bank interest rate meeting.
* Asian shares were down for the third consecutive day on a drop in commodities, moving further away from a three-year high tested last week.
* Weak economic figures heightened stock investors' anxiety over the extended rally, knocking U.S. shares lower for a third day on Wednesday.