Automaker Volkswagen AG said Friday that its net earnings more than doubled last year as revenues grew by more than a quarter and the company benefited from accounting factors related to its stalled takeover of Porsche.

Volkswagen earned €15.41 billion ($20.5 billion) in 2011, according to a preliminary earnings statement, up from €6.84 billion the previous year and better than analyst expectations for €13.9 billion. One euro is worth $1.33.

The company, which is to release its full earnings report on March 12, gave no fourth-quarter figures.

Revenues rose 26 per cent to €159.3 billion from €126.9 billion in 2010, again above market forecasts for C156.2 billion as polled by FactSet.

Volkswagen sold nearly 8.27 million vehicles last year, a 14.7 per cent rise from the previous year's figure of 7.2 million and putting it ahead of Japan's Toyota.

The company said that its pre-tax profit for 2011 soared to €18.93 billion from €8.99 billion the previous year. It credited "positive effects from equity-accounted investments" and from its revaluation of put and call rights related to Porsche.

The takeover of Porsche has been stalled by legal issues, although the companies already co-operate extensively.    Volkswagen already had announced a large accounting addition from revaluing options when it released its third-quarter results, saying at the time that the move added €6.8 billion to its results.

Operating profit for the full year, which does not include those one-time effects, was up to €11.27 billion from €7.1 billion a year earlier, just short of the €11.5 billion analysts had forecast.

Shares in the company slipped 0.3 per cent to €138.80 in Frankfurt trading.