March 17, 2014 12:57 p.m

CEO Says the Company Is Working to Finish the Probe by the End of March

RIO DE JANEIRO—Brazilian state-run energy giant Petroleo Brasileiro SAPETR4.BR +0.21% is still working on an internal investigation of allegations that it accepted bribes from Netherlands-based SBM Offshore NV, the company’s chief executive said Monday, amid mounting political tension around the firm.

Petrobras CEO Maria das Gracas Foster said last month that the company had begun its investigation the week ended Feb. 16 and was “working to finish it in 30 days.” On Monday she denied having given a hard deadline, saying that “we’re very close” to finishing the internal probe and are “working” to finish it by the end of March.

The investigation surrounds allegations that Petrobras officials accepted $139.2 million in bribes from SBM Offshore, a supplier of offshore oil vessels. Those suspicions arose last year when a former SBM Offshore employee published on the Internet parts of documents from the early stages of an internal audit on “potentially improper payments” made in several countries between 2007 and 2011.

The case has attracted increased scrutiny during the past week or so in Brazil, which is set to hold presidential elections in October and where the government plays an active role in Petrobras’ decision-making. Brazilian Finance Minister Guido Mantega serves as Petrobras’ chairman.

Brazil’s Congress last week voted to create a commission to investigate the bribery accusations in what was seen as a legislative defeat for President Dilma Rousseff, who is widely expected to seek re-election

Brazil’s Federal Police are also launching a probe into the SBM Offshore allegations as well as possible irregularities in Petrobras’ troubled purchase of an oil refinery near Houston. In the latter case, Petrobras spent about $1.2 billion—nearly a third of which were legal fees—to acquire an asset that the previous owner, Dutch commodities trader Transcor Astra Group SA, had bought in 2005 for around $60 million.

Petrobras’ shares have fallen 25% since the end of last and are trading near their lowest levels since 2008, weighed down by concerns about mounting debt and delayed expansion plans.

For its part, SBM Offshore has said the leaked documents that appear to implicate Petrobras are outdated, and has suggested that the former employee who published the documents was seeking to extort the company. SBM Offshore’s internal investigation is focused on payments made in two countries in Africa and another elsewhere, and the company is working with U.S. and Dutch authorities.

“From our end, based on our internal investigation, we have no conclusive proof of improper sales practices in countries outside Africa,” said Nicolas Robert, SBM Offshore’s head of investor relations.