Mercedes-Benz is to take over distributing the Smart brand from Penske Automotive Group in a move that appears to have been prompted by corporate model range average fuel economy rules.

The pair said in a statement they had "started discussions to transition the distribution rights, management, sales and marketing activities" and expect to complete the move by the end of June.

"The proposed change marks a further step in implementing the future growth strategy of the Smart brand. It also reflects last year’s reorganisation at headquarters in Germany, where its is now managed as an independent brand but is fully integrated into Mercedes-Benz Cars business unit of Daimler."

The statement added: "The addition of the fuel efficient [petrol and] electric vehicles to the Mercedes-Benz product portfolio underscore the company’s commitment to meet even more stringent fuel economy standards in the future."

The number of US Mercedes-Benz dealers selling smart cars will drop to the mid-50s, down from the current 75 at dealerships owned by the Penske group, but would later be expanded, a Mercedes-Benz spokesman told Reuters.

Plans for a five-door hatchback supplied on an OEM basis by Nissan Motor have been axed and the next new Smart developed as a global car by a Daimler-Renault/Nissan joint venture.

US sales of the Smart Fortwo in 2010 were 5,927, down from 14,595 in 2009 and 24,622 in 2008, the news agency noted.