Car seller United Auto Group ( UAG) inked a pact to buy Cush Automotive Group of San Diego, a firm that will add six dealerships to its holdings.

"Once completed, the acquisition of these franchises will provide UnitedAuto with additional scale to complement our existing operations in the Kearny Mesa area of San Diego," the company explained in a press release Tuesday.

Financial terms of the transaction weren't disclosed, but United Auto expects the dealerships to generate about $300 million in yearly revenue. The purchase should close during the first quarter.

Shares of United Auto, based in Bloomfield Hills, Mich., were down 62 cents, or 1.9%, to $32.64.