Nidec Shares Tumble After Scandal Spreads to Product Quality

Nidec Corp. is facing renewed investor backlash after disclosing quality control misconduct involving motors and other products, compounding the challenges confronting a once-admired manufacturer on top of accounting problems and the exit of its charismatic founder.

Shares of the world’s largest maker of precision motors fell as much as 18% in morning trading in Tokyo, the steepest decline in six months, after Kyoto-based Nidec said the issues involve changes made to materials, processes and designs without approval.