TOKYO (TheStreet) -- Japanese automaker Mazda reportedly plans to end its joint venture with Ford(F) and stop making cars in the U.S. Mazda and Ford operate the AutoAlliance International plant in Flat Rock, Mich. as an equal partnership. Mazda is considering selling its stake to Ford and switching production of cars it makes in the U.S. to Japan starting in 2013, according to Nikkei, a Japanese financial daily. Mazda said it wouldn't comment on speculation. "Mazda and Ford are jointly studying various possibilities for AAI, and we have nothing to announce at this time," Mazda said. -- Written by Joseph Woelfel