Globex S&P futures trading limit down 60.00 below previous day's SPX cash close.

Stocks tumbled around the world and U.S. index futures fell on increasing concern the weakening global economy will decrease earnings.

Nikkei 225 down 9.60%, DAX 30 down 8.96%. WTI Crude oil $64.50. Copper down 2.50%. Gold $690.

Volatility Index S&P 500 Options-VIX at 67.80; 10-day moving average is 63.07.

Volatility Index NASDAQ 100-VXN at 69.83; 10-day moving average is 67.16.

NASDAQ 100-QQQQ overall implied volatility at 53; 26-week average is 33.

Semiconductor Holders Trust-SMH overall volatility at 49; 26-week average is 33.

Russell 2000-IWM overall implied volatility at 51; 26-week average is 33.

Financial Select Sector-XLF overall volatility at 70; 26-week average is 44.

Option Update is provided by Stock Specialist Paul Foster of theflyonthewall.com

The New York Times reports that global stock markets are tumbling. Nobody really knows why but the latest theory is that investors are concerned about the capital problems at Fannie Mae (NYSE: FNM) and Freddie Mac (NYSE: FRE) about which I posted yesterday.

Here's a survey of some of the global market damage:

• Nikkei 225 stock average fell 2.5%
• The Hang Seng index in Hong Kong down 3.3%
• S&P/ASX 200 index in Sydney declined 1.4%
• In London morning trading, the FTSE 100 index was down 2.7%
• DJ Euro Stoxx 50 index, of euro zone blue chips, fell 2.3%
• DAX in Frankfurt fell 2.4%
• CAC 40 in Paris sank 2.4%

Markets in Asia fell:

The Nikkei traded down 4% to 13,088. Sony (NYSE: SNE) fell 4.5% to 4,880. Toyota (NYSE: TM) fell 4.1% to 5,340.

The Hang Seng fell 4.3% 24,054. China Life (NYSE: LFC) fell 6.3% to 31.40. PetroChina (NYSE:PTR) fell 5.7% to 11.2.

The Shanghai Composite dropped 7.2% to 4,419.

Data from Reuters.

Douglas A. McIntyre is an editor at 247wallst.com.