Some $4 trillion has been wiped off the value of world stocks this month on concerns the euro zone debt crisis is spreading to Italy and Spain and hurting Europe's banking system, and the global economy is falling into recession.

The sum wiped off the MSCI All-Country World Index <.MIWD00000PUS> - about one seventh of its value - is almost equivalent to the size of combined economies of Italy, Spain, Portugal, Ireland and Greece.

The sell-off this week knocked nearly $1.6 trillion off the market capitalization of the global benchmark after last week's $2.5 trillion loss.

The valuation of the benchmark is currently $24.84 trillion.

The U.S. S&P 500 <.SPX> alone has lost more than $710 billion this week after losing $850 billion the previous week, while European shares measured by the MSCI Europe <.MSCIEU> have lost almost $500 billion this week.

(Reporting by Dominic Lau; Editing by David Cowell)

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