NZX-listed Trade Me said it had bought Auckland-based vehicle data experts MotorWeb for $19.5 million in cash.
The deal is conditional but Trade Me said it expected it to be completed later this month.
MotorWeb is an online business that packages and sells motor vehicle information and reports to finance companies, insurers, car dealers and the public.
The company was founded by Patrick Costigan in 1997 and began trading in 2000. It is based in Auckland and operates in both New Zealand and Australia.
Trade Me chief executive Jon Macdonald said the MotorWeb business had potential to complement its existing Trade Me Motors business.