Aabar's purchase of shares in Daimler, which makes Mercedes-Benz cars and is the world's leading heavy truck manufacturer, will help bolster the carmaker's finances.

The investment highlights the continuing financial power of some Gulf region states despite the global downturn.

The second largest shareholder in Daimler is Kuwait's main sovereign wealth fund, which has a 6.9 per cent stake in the company.

Last December, Aabar agreed to purchase AIG Private Bank, the Swiss-based wealth management arm of the American International Group.