Brazil 's state-run energy company Petroleo Brasileiro SA (PBR, PETR4.BR), or Petrobras, on Friday launched its offer to raise about $64 billion from the world's largest-ever sale of shares to finance a massive investment program over the next five years.

The company plans to invest $224 billion over the next five years, with much of the money earmarked to develop massive oil deposits discovered in deep waters off the country's south-central coast. The company aims to double oil output to 3.9 million barrels a day by 2014, making
Brazil the world's fifth-largest oil producer and likely placing it among the top 10 in terms of exports.

Petrobras will offer a total of 3.75 billion shares, of which 2.17 billion would be voting stock and 1.58 billion would be preferred shares, the company said Friday in a statement. Based on Thursday's closing prices for Petrobras' shares, the offer could raise around 111 billion Brazilian reals ($64.1 billion).

Petrobras will offer 80% of the new shares to its existing shareholders, the largest of which is the Brazilian government. In what is essentially an oil-for-shares deal, Petrobras earlier this week agreed to pay the Brazilian government $42.5 billion for the rights to produce 5 billion barrels of crude oil from those offshore reserves.

The company will also seek fresh capital from non-government investors in
Brazil and abroad, although if there isn't sufficient demand the government has said it may step in to buy up an even larger amount of the new shares.

That would further increase the government's stake in Petrobras, which has long been a concern of minority shareholders.

Bank of America Merrill Lynch, Bradesco BBI, Citibank, Itau BBA, Morgan Stanley, Banco Santander, BB Investimentos, BTG Pactual, Credit Agricole, Credit Suisse, Goldman Sachs, HSBC, JP Morgan, Societe Generale, Espirito Santo Investment, Deutsche Bank, J. Safra and Banco Votorantim will coordinate the operation.