Trade Me is buying the rest of vehicle dealer collator AutoBase for $11.5 million in cash.
The company already has a quarter stake in AutoBase, which aggregates listings from car, truck, motorcycle and boat dealers, which Trade Me then advertises on its Trade Me Motors site.
Chief executive Jon Macdonald says the online auctioneer purchased the remainder of AutoBase from co-founders Hamish Lusk and David Paviour to bring the operation in line with its property and jobs arms.
All of Autobase's 16 staff will be kept.
All up, Trade Me paid $15.5 million for Autobase, which made a profit of $2.3 million in the year to March.