Internet Brands, which operates consumer interest websites and offers software to small and medium-sized businesses, has acquired automotive site publisher High Gear Media.

Terms of the deal were not disclosed.

Internet Brands and its websites reach more than 100 million monthly visitors by servicing four markets: auto, health, legal and home and travel. A company spokesman said the acquisition expands the reach of its oldest category – automotive – by increasing that division’s uniques by 25 percent to 35 million monthly visitors.

High Gear Media’s properties, such as luxury car news site MotorAuthority.com and hybrid and electric car guide GreenCarReports.com, target specific and often high-end auto consumer interests. The company is expected to stay at its Menlo Park operations.

“Consumers will continue to benefit from top-tier automotive content and buying advice, while auto OEMs and dealers will have access to exciting new advertising opportunities at unprecedented scale,” said Bob Brisco, Internet Brands’ chief executive, in a statement.

Internet Brands originally launched as car-buying site CarsDirect.com in 1998 out of the Pasadena incubator Idealab. The El Segundo firm rebranded as Internet Brands in 2006. The company, which was acquired by global investment firm KKR in June, has roughly 1,600 employees.

Staff reporter Melissah Yang can be reached at [email protected]. Follow her on Twitter @MelissahYang for the latest in L.A. tech news.