General Motors Co. said it will launch a new, online used vehicle market called CarBravo that will allow the automaker and its dealers to challenge Carvana Co., Carmax Inc. and others profiting from selling second-hand vehicles.

GM's CarBravo site will aggregate vehicles owned by Chevrolet, Buick and GMC dealers, as well as cars and trucks that GM's consumer finance arm controls after taking them back from rental car agencies or vehicle leases. GM officials said the company's dealers have about 400,000 used vehicles in stock.

GM said consumer launch of CarBravo will come in the spring.