BDML Holdings has bought motor specialist Sabre Insurance Company from the CGNU Group.
The deal, still subject to regulatory approval, will allow Sabre to continue to operate its headquarters at Dorking as an independent company. Sabre was valued at £18m in December 2000.
BDML chief executive Keith Morris said Sabre complemented BDML's role as a specialist insurance services provider.
He said no Sabre staff would lose their jobs. "Sabre's success is based on being a focused business, closely controlling and coordinating key business processes," he said.
Norwich Union insurance operations director Cathryn Riley said the company had done a thorough review of Sabre over the past year and "concluded that best value could be created by the sale of the business".
"We remain committed to the non-standard motor market," she said.