It says two other groups have also shown an interest.
The company, which has no showroom and carries no stock, is enjoying a financial boom, with an 85% rise in orders compared to last year and a 240% growth in revenue.
Visitors have access to facilities offering everything from car sales to finance. This has helped make the site the second biggest portal of its kind, with 7,500 visitors per day and a turnover of £20m.
Managing director Terry Hogan says: “We have a compelling proposition that car dealer groups are now recognizing as the best in the industry. While it is flattering that major plcs take an interest in the company, the board feels we can get better value at the end of 2007 than now.”
He is working with a number of dealers, helping them to improve their website offering.