PwC Kyoto refused to sign off on Nidec's accounts despite booking impairment charges of ¥1tn ($6.36bn) following an accounting fraud. The auditor cited inability to obtain sufficient evidence for an opinion as the crisis continues to spiral. Nidec chief executive Mitsuya Kishida resigned earlier this week ahead of fresh impairments being unveiled.

The supplier to Volkswagen and BMW has cut ties with founder Shigenobu Nagamori, whose 'culture of excessive pressure' has been blamed for many issues. PwC Kyoto noted ongoing involvement in financial reporting by individuals aware of improper accounting practices or who provided false statements. The disclaimer follows fresh writedowns and is another blow to Nidec's efforts to resolve the accounting fraud that inflated profits.

The scandal has hit investor confidence and sent shares down sharply. Nidec could face delisting in October if it cannot prove adequate internal control overhauls. Japan's biggest accounting fraud involved cumulative ¥1.11tn in charges.