Many emerging-market currencies are falling against the dollar

SINCE January 22nd the Argentine peso has fallen by 14%. It may be the most dramatic plunge among emerging-market currencies in recent days, but it is hardly alone. From Turkey to South Africa to India, the currencies have been weakening against the American dollar. Most have shed between 10% and 20% of their value since May, when Ben Bernanke, the outgoing Fed chairman, uttered the word "tapering", code for reducing America’s bond-buying under quantitative easing. Each market has specific worries. South Africa and Turkey have gaping current-account deficits. Ukraine and Thailand are riven by political protests. Brazil is vulnerable to China’s slowdown. Argentina is running out of international reserves with which to prop up the peso. But when markets start falling, contagion is always a worry.

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