Oct. 22 (Bloomberg) -- Mazda Motor Corp., a third owned by Ford Motor Co., plunged the most in more than eight years after billionaire Kirk Kerkorian sold part of his stake in the U.S. carmaker and the yen strengthened to a four-year high against the euro.

Mazda dropped 37 yen, or 13 percent, to close at 247 yen on the Tokyo Stock Exchange. It was the biggest drop since February 2000.

Ford, reeling from plunging U.S. car sales, may cut its stake in Mazda to raise cash as Kerkorian considers unloading the rest of his stake in the U.S. carmaker. The yen's rise against the euro also sparked concern Mazda's repatriated earnings from Europe, where it earns more than half of its operating profit, may be eroded by a strong local currency.

``Uncertainty about the Ford-Mazda relationship may be fueling the sell-off,'' said Yoku Ihara, head of equity research at Retela Crea Securities Co. in Tokyo. ``The stronger yen is also a negative factor.''

The yen touched 127.01 per euro, the strongest level since April 2004, and traded at 128.57 from 130.80 yesterday.

To contact the reporter on this story: Makiko Kitamura in Tokyo at mkitamura1@bloomberg.net.

Last Updated: October 22, 2008 03:14 EDT