UPDATE 1-Paper Excellence delivers formal bid for Brazilian pulp producer Fibria -sources

Fibria -sources@ (Updates with information from sources, details on bid)

SAO PAULO, March 12 (Reuters) - Netherlands-based wood pulp producer Paper Excellence has delivered a formal bid to acquire buy Brazil's Fibria Celulose SA, two sources with direct knowledge of the matter said on Monday.

According to the sources, which asked for anonymity because the matter was still private, Paper Excellence's bid values Fibria at 40 billion reais ($12.3 billion), which exceeds current market capitalization of 37.2 billion reais.

Paper Excellence, controlled by the Wijaya family, decided to bid after reports of Fibria negotiations with rivals, the sources added.

Brazilian pulpmaker Suzano Papel e Celulose SA approached Fibria's shareholders in recent weeks to discuss a merger. Last week Paulo Rabello de Castro, chief executive officer of Brazilian development bank BNDES, confirmed the talks between the companies.

BNDES is a common shareholder in Fibria and Suzano. Brazilian newspaper Valor Econômico reported the bid earlier.

Valor had reported that Chile's Arauco, a subsidiary of industrial conglomerate Empresas Copec SA, and Finland's UPM were also interested in acquiring Fibria.

Paper Excellence, controlled by the Wijaya family, which also owns Indonesia's Asia Pulp & Paper Co Ltd, has acquired Eldorado Brasil Celulose SA last year for $4.7 billion. Fibria and Eldorado have units in the same city, Três Lagoas, in Mato Grosso do Sul state.

Banco BTG Pactual SA is advising Paper Excellence in the acquisition. Fibria, Paper Excellence, and BTG Pactual did not immediately respond to requests for comment. ($1 = 3.2559 reais) (Reporting by Gram Slattery Editing by Jeffrey Benkoe and David Gregorio)