The deal, for an undisclosed sum, will see Brands Hatch, Oulton Park, Cadwell Park and Snetterton sold to a new company led by Palmer called MotorSport Vision.
Interpublic will continue to lease the Silverstone racing track, which is home to the British Grand Prix and will rename its Brands Hatch Circuits racing business as Silverstone Motorsport Limited.
Interpublic has been selling off non-core assets as it seeks to deal with debt accrued after its acquisition spree in the late 1990s. This was compounded by losses in its motorsports division, which lost $135.8m (£74.9m) in 2001. However, reports say that the company is likely to have received far less than the £120m it paid four years ago when it bought Brands Hatch Leisure.
It is good news for the British motor racing industry, which had feared that the four tracks could be bought by property developers and used for something other than motor racing.
Palmer, who was a doctor before becoming a F1 racing driver, already runs a company called Bedford Motorsports that sells corporate packages as well as "track days", which give owners of fast cars the chance to drive them at high speeds without fear of being caught by speed cameras.
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