Mazda Motor Corp. plans to stop making sedans at a Michigan plant shared with Ford Motor Co. since 1992 as part of efforts to improve efficiency and cut costs.

Production of the next-generation Mazda6 sedan will be moved to Hofu, Yamaguchi Prefecture, from the AutoAlliance International factory, or AAI, in Flat Rock, Michigan, Mazda said Monday. It didn't say when the change will take effect.

"The decision was made after carefully assessing all risks and opportunities, including global needs, changing demand in North America and exchange rate exposure," Chief Executive Officer Takashi Yamanouchi said. "We are committed to working with Ford, our joint venture partner in AAI, to identify potential future opportunities for the plant."