Last year Tamsen's company achieved annual sales of 75 million euros with unit sales of 700 cars in 2004.
Now Tamsen has sold the company to the US United Auto Group (UAG). UAG bought 75 percent of Tamsen company shares last June.
When Tamsen, 43, unexpectedly offered to sell his remaining share "at a fair price," UAG owner Roger Penske immediately jumped at the opportunity.
Jens Werner, head of UAG Europe, told Automobilwoche that Tamsen will continue to act as an advisor to the company.
Tamsen specializes in selling exclusive Ferrari, Maserati, Aston Martin, Rolls-Royce, Bentley and Lamborghini brands.
Tamsen's new yacht company will continue to do business with the Penske Group.
The yachts that Tamsen and his wife will be selling from the island of Mallorca in the Mediterranean -- prices start at 50 million euros -- are powered by engines by VW Motori, among others.
Penske Corp. owns the Italian engine plant.