But central bankers cannot afford to be predictable when intervening in currency markets, for to do so is to offer speculators a one-way bet.

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The first is a rise in global inflation and the second is emerging markets intervening in currency markets and then diversify their holding with more gold and less U.S. dollars.

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At this historic meeting, the finance ministers of France, West Germany, Japan, the United States, and the United Kingdom signed the Plaza Accord in which they all agreed to depreciate the U.S. dollar in relation to the Japanese yen and German deutschemark by intervening in currency markets.

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Even if interest rates hit zero, they argue, central banks can use other measures, such as flooding the banking system with money, buying government bonds or intervening in the currency markets.

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Some experts then proclaim that intervening in the foreign markets to keep up a currency's value is futile.

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