The rouble's sharp fall against the dollar meant Rosneft (>> Rosneft' NK OAO) - one of the biggest contributors to state revenues - posted just 1 billion roubles (10 million pounds) in net profit in the third quarter.

Rosneft - 69.5 percent state owned and run by Igor Sechin, an ally of President Vladimir Putin - said net debt was $45 billion (30 billion pounds) at the end of September and repayments would be $19.5 billion in 2015.

On Tuesday it said it was adopting "hedge accounting", under which currency gains or losses related to debt "are temporarily recognised within other comprehensive income being part of equity with no effect on profit or loss for the period".

"Once the hedged operation occurs and revenue is recognised, the related exchange differences temporarily held within equity are released to profit or loss for the period, within revenue and EBITDA," it said.

The accounting change, backdated to Oct. 1, has already helped BP (>> BP plc) beat fourth quarter 2014 expectations by booking a $470 million profit from its 19.75 percent stake.

Raiffeisenbank analyst, Andrey Polischuk, said the market

been expecting Rosneft to show a significant losses relating to foreign exchange in the fourth quarter which could have meant the company showing a loss for the year as a whole.

"Now, it (a potential FX loss) should not affect dividends Rosneft are paying, including to the state budget... If there was a loss and no dividends, the question of the company's effectiveness could have arisen," Polischuk said.

(Reporting by Katya Golubkova and Vladimir Abramov; Editing by Timothy Heritage and Louise Ireland)

Stocks treated in this article : Rosneft' NK OAO, BP plc