Foreign bank deposits at the Federal Reserve have more thandoubled to $715 billion from $350 billion since the end of 2010amid Europe's debt turmoil, buttressing the dollar's status as theworld's reserve currency.

Forty-seven non-U.S. banks held balances of more than $1 billionat the New York Fed as of Sept. 30, up from 22 at the end of 2010,according to a survey of 80 financial institutions by ICAP Plc, theworld's largest inter-dealer broker. The dollar has appreciated 7.2percent since Standard & Poor's cut the nation's AAA creditrating Aug. 5, the second-best performance after the yen amongdeveloped-nation peers, according to Bloomberg Correlation-WeightedCurrency Indexes.

A budget deficit of more than $1 trillion, a deadlock amongCongressional supercommittee members on spending cuts and 9 percentunemployment haven't deterred investors from seeking safety in theworld's biggest economy. The euro has been undermined by theregion's sovereign debt crisis, while the Swiss franc and yen havefallen as their governments buy billions of dollars to weakenthem.