Administrators called in to Seward (Wessex) are allowing the Vauxhall and Chevrolet group to continue trading while a buyer is sought.
Smith & Williamson were appointed to the business, which has dealerships in Poole, Bournemouth, Christchurch and Blandford Forum, on Tuesday after it entered a financial crisis.
The joint administrators are Gregory Palfrey and Stephen Adshead.
Seward's Bournemouth business was General Motors' first brand centre in Europe, opening in 2004 following £4.5m investment as a two-storey flagship for the Vauxhall, Saab and Chevrolet brands.
Seward last year acquired naming rights to Bournemouth AFC's stadium.
Seward Accident Repair Centres, a separate company, is not in administration, nor is Seward Renault and Suzuki in Portsmouth.