Dealership chain Cambria Automobiles has acquired the Summit Auto Group, making it one of the top 30 dealerships in the UK.
Businesses that will change ownership include Grange, Invicta Ford, Dees Ford and Doves Volvo.
Almost all of these dealers' sites are in south-east England, with two in Devon.
Cambria will also take on the Jaguar and Aston Martin dealers that were part of Summit.
The price paid by Cambria for the Summit Auto Group has not been revealed.
The rights of anyone who has bought a car from these dealerships will be unaffected.