Nidec Corp.'s shares jumped as much as 19% in Tokyo trading after an investigation into its accounting scandal found systemic issues with financial reporting but not its manufacturing operations. The stock pared gains to trade around 5% higher by mid-morning. The company faces ¥250 billion ($1.6 billion) in impairment charges and warned of additional losses that could impact past financial results.

Investigators uncovered at least 1,000 instances of improper accounting spanning subsidiaries in Italy, Switzerland, and China, as well as its car inverter business. The accounting irregularities included inflated raw material values, incorrect customs declarations, and labor costs improperly classified as fixed assets. Since the scandal surfaced in June, Nidec has delayed financial results, suffered a credit rating downgrade, and faces potential delisting from the Tokyo Stock Exchange.

Founder Shigenobu Nagamori stepped down as chairman emeritus, with additional executive departures announced Tuesday including the acting chairman and CFO. Despite the turmoil, Nidec reported 3.9% revenue growth to ¥678 billion in the quarter ended December 31. The share price surge suggests short-sellers may be covering positions, though the Tokyo Stock Exchange's delisting decision remains pending.