First, it has to find a way for Brazil's now-floating currency to cohabit with Argentina's rigid currency board.

ECONOMIST: Mercosur’s malaise | The

Argentina had a rigid currency board.

ECONOMIST: Latin American markets

Though the financial markets have recently taken a slightly more relaxed view of Argentina's problems, under the country's rigid currency-board scheme any firm recovery from its current lengthy recession depends on inflows of money from abroad.

ECONOMIST: Argentina

Either countries should float their currencies (or adopt much wider bands) or they should adopt the rigid fixity of a currency board or even currency union.

ECONOMIST: Storm clouds from Brazil

The most important learning has been the need to build a rigid financial structure and business model where the dash board is always 100 percent updated and accurate and that the out come can never be better than the quality of our MFI partners.

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Argentina, Latin America's fastest-growing economy last year, has the most rigid exchange-rate system of all, with a currency board that fixes by law the value of the peso at parity with the dollar, and thus limits the money supply to the level of foreign currency reserves.

ECONOMIST: Latin America seeks shelter