Stock Markets May 12, 2026 09:51 PM

Nidec Shares Plunge After Company Flags Suspected Quality-Inspection Misconduct

Motor maker reports suspected unauthorised changes to products; stock tumbles while Nikkei posts mild gains

By Maya Rios

Nidec Corp shares fell sharply after the company disclosed suspected improper conduct related to quality inspections, including unauthorised changes to materials, processes and designs in some products. The firm said no immediate product functionality or safety issues were found and that it may set up an investigation committee. The report follows a media account alleging quality tampering in over 1,000 cases and comes amid the companys recent accounting revisions that trimmed net profit expectations by 160.7 billion yen for 2020-2025.

Nidec Shares Plunge After Company Flags Suspected Quality-Inspection Misconduct

Key Points

  • Nidec confirmed suspected improper conduct in quality inspections, including unauthorised changes to materials, processes and designs.
  • Shares of Nidec fell up to 18% to 2,329.0 yen, while the Nikkei 225 saw mild gains the same day.
  • Nidec said it found no immediate product functionality or safety issues and is considering the creation of an investigation committee.

Tokyo - Shares of Nidec Corp plunged on Wednesday after the motor and drive systems manufacturer confirmed it had uncovered suspected improper conduct connected to quality inspection processes.

Nidec stock dropped as much as 18% to 2,329.0 yen, diverging from the Nikkei 225 index which posted modest gains during the same trading session.

In a formal statement, the company said it identified "suspected improper conduct" affecting certain products. The irregularities cited include alterations to materials, changes to processes and modifications to designs that were carried out without obtaining approval from customers.

Nidec emphasized that, based on its initial findings, it had not detected any problems that would immediately compromise product functionality or safety. The company also said it is considering establishing an investigation committee to look into the matter further.

The companys announcement followed a report from Nikkei Asia that said the firm engaged in quality tampering in more than 1,000 cases. That account added a new operational concern for Nidec at a time when the company is already managing fallout from accounting issues.

Last month Nidec disclosed accounting revisions that are expected to reduce net profit by 160.7 billion yen for the period from 2020 through 2025, a figure the company presented as the impact of prior accounting adjustments. Until now, the misconduct allegations had focused on accounting practices rather than manufacturing operations.

While the companys recent statement indicates no immediate functional or safety failures tied to the suspected inspection misconduct, the report of potential tampering raises fresh questions about oversight of Nidecs core manufacturing processes. The companys potential formation of an investigation committee suggests it intends to probe the scope and causes of the suspected improper conduct.


Market context

Nidecs share move was substantial relative to the broader Japanese equity market, where the Nikkei 225 registered only mild gains on the same day. The divergence highlights the company-specific nature of the news and its immediate effect on investor sentiment toward Nidec.

Risks

  • Potential operational oversight concerns in manufacturing processes could affect investor confidence in industrial and industrial supply sectors.
  • Ongoing investigations or further revelations could compound existing financial strains tied to the company's recent accounting revisions, impacting corporate credit and investor sentiment.
  • Uncertainty around the scope of the alleged quality issues - including the number of affected cases reported - may lead to prolonged scrutiny of Nidec's governance and internal controls.

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