* Gloomy economic picture fuels risk aversion * Financials, energy shares fall before the bell * For up-to-the-minute market news, please click on [STXNEWS/US] (Updates with retailers outlook, energy and financial shares, data schedule, prices) By Ellis Mnyandu NEW YORK, Dec 1 (Reuters) - U.S. stock index futures fell on Monday as concerns about the deepening world economic slump reduced the appetite for risk and investors fretted about the start of what they fear will be a bleak holiday buying season. With the start of the new month, U.S. benchmark indexes could open 2 percent or more lower, a drop that will extend a global equity rout that hurt stocks in Asia and sent European indexes sliding nearly 3 percent. Stocks had their best weekly showing in about 30 years last week, but November was one of the worst months since 1987. Grim manufacturing figures from China, the world's fourth largest economy, and from Europe offered yet more evidence of mounting deterioration in the world's economy. Shares of financial companies fell before the bell, with Citigroup (C.N: Quote, Profile, Research, Stock Buzz) down 5 percent. A drop in oil prices weighed on energy shares, sending Exxon Mobil (XOM.N: Quote, Profile, Research, Stock Buzz) 3 percent lower. Yields on benchmark 10-year Treasuries sagged to fresh five-decade lows as investors scurried toward the relative safety of government debt. "We still have a lot of things to be concerned about," said Arthur Hogan, chief market analyst at Jefferies & Co in Boston. "We have a week that's full of economic data, and on top of that everybody is going to be trying to slice and dice the consumer and how they are faring." S&P 500 futures SPc1 were 24.10 points lower 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 DJc1 slid 193 points, and Nasdaq 100 NDc1 tumbled 29 points. Consumers made repeat trips to U.S. stores and spent more on bargains this holiday weekend, but analysts said the early rush was unlikely to save retailers from a bleak sales season. For details, see [ID:nN30476271] Investors would get a peak into how individual companies are faring when major U.S. retailers post monthly sales figures on Thursday, a day before the government's release of the November unemployment report, including non-farm payrolls. Shares of financial services companies were likely to be among the top drags after influential bank analyst Meredith Whitney of Oppenheimer & Co said the U.S. credit-card industry may cut $2 trillion in credit lines over the next 18 months due to caution about risk and regulatory changes, leading to sharp contraction in consumer spending. Shares of Citigroup were down 5 percent at $7.90, while those of Bank of America (BAC.N: Quote, Profile, Research, Stock Buzz) declined 1.5 percent to $16. Goldman Sachs (GS.N: Quote, Profile, Research, Stock Buzz) dropped nearly 3 percent to $76.85. Exxon Mobil shares fell 3.7 percent to $77.15 before the bell as oil prices fell on concerns a faltering global economy will hurt energy demand. U.S. front-month crude CLc1 fell 5.1 percent to $51.59 a barrel. China's manufacturing industry slumped in November as new orders, especially from abroad, tumbled in the face of deepening economic gloom and financial uncertainty. A report on November U.S. manufacturing from the Institute for Supply Management is due at 10 a.m. (1500 GMT) (Editing by Kenneth Barry)

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