RIO DE JANEIRO: Brazil's state-controlled oil producer Petroleo Brasileiro SA said investors' appetite for a global bonds buyback exceeded $4 billion initially offered in Sept. 10, the company said in a statement on Thursday.

The offers expired on Wednesday and the settlement date is Sept. 21, said Petrobras, as the state-controlled company is known.

The buyback is part of Petrobras' strategy to extend debt maturity and reduce its financial costs.

The offer totaled $3,500,381,246.30, Petrobras said. The producer hasn't accepted all the offers, which is allowed by the buyback terms when the total amount offered by investors exceeds the limit, Petrobras said.