Brazil's central bank calls auction to buy dollars

SAO PAULO, Nov 11 (Reuters) - Brazil's central bank offered to buy dollars on the spot foreign exchange market on Wednesday in an ongoing effort to boost international reserves and soak up greenbacks pouring into the economy.

The bank has bought about $21 billion on the spot market since May 8, including about $6.7 billion in October, to soak up dollar liquidity and prevent further appreciation of Brazil's currency, the real.

Brazil's currency (BRBY) was trading 0.47 percent weaker at 1.725 per U.S. dollar shortly after the central bank's announcement.

(Reporting by Silvio Cascione; writing by Peter Murphy; editing by Jeffrey Benkoe)