RIO DE JANEIRO, Jan 6 (Reuters) - Brazil's state-run oil company Petrobras aims to write off all of an expected multi-billion-dollar loss stemming from a corruption scandal when it releases unaudited third-quarter results this month, a source with direct knowledge of the company's thinking told Reuters.
The loss will result from the write-down of assets whose value was inflated by corruption. Petrobras will likely calculate the amount using the "present value of discounted future cash flows" rather than the "fair price" accounting method, said the source, who asked for anonymity because they were not authorized to speak on the matter.
"The company wants to put this behind it as quickly as possible," the source said. "It is determined to take all of the loss now as re-calculating past results is too complicated and figuring out the exact value of corruption and overcharging is almost impossible."
Petrobras did not immediately respond to a request from Reuters for comment.
When and how to take the still unknown loss from Brazil's largest-ever corruption scandal, which included price-fixing, bribery and political kick-backs, will determine how quickly Petroleo Brasileiro SA, as Petrobras is formally known, resumes normal operations and regains investor confidence.
Petrobras was unable to release third-quarter results after an investigation, arrests and indictments of company officials and Petrobras contractors prompted auditor PricewaterhouseCoopers in November to refuse to certify its financial statements.
Since then, Petrobras, already the world's most-indebted and least-profitable major oil company, has been cut out of debt markets and seen its stock fall more than 40 percent to trade at its lowest levels in a decade.
The company in December promised to release unaudited third-quarter results by the end of January.
The present value of discounted future cash flows is the best way to write down the assets, said Reginaldo Gonçalves, coordinator of accounting sciences at Faculdade Santa Marcelina, a Sao Paulo university-level academy.
The method prices assets based on what Petrobras expects them to earn rather than on the market price of similar oil refineries, oil platforms and other assets, he said.
"The key will be the parameters - oil price, exchange rate - that Petrobras uses to set the new values," Gonçalves said. "If it isn't transparent, it won't convince investors the accounts are correct."
Additional losses could be taken in the future if new corruption cases come to light and some losses could be reversed if assets perform better than first expected, he added. (Reporting by Jeb Blount; Editing by Alan Crosby)