Marshall has completed its acquisition of Mercedes-Benz retail outlets in the north west from Pendragon.
The acquisition covers seven franchised businesses in Blackpool, Preston, Blackburn, Bolton and South Lakes, plus Smart in Blackpool and Bolton. Collectively they are the Mercedes-Benz North West Market Area (MA5).
The additional dealerships brings Marshall's total to 62 businesses and the addition of two German brands - a first for the group - to 25. With the addition of 170 staff, Marshall's headcount is now 1,980.
Franchise director for the acquired sites is Stuart Faid.
Marshall chief executive Daksh Gupta said: "This is a hugely significant deal for us. The new businesses will take our turnover to a running rate of around £675 million, nearly double our 2008 turnover."
The acquisition, he said, fits with Marshall's strategy to expand with "strong partnerships in scalable territories".
"The north west represents a great opportunity for us with one of the world's leading brands and we are hugely honoured to be approached by Mercedes-Benz regarding this acquisition."
Pendragon chief executive Trevor Finn said the proceeds of the sale would go towards reducing the company's borrowings.