Shares of Chubu Electric Power Co. experienced a significant drop following the announcement of an internal investigation into potential irregularities in the compilation of safety data for its nuclear power plant. The stock price fell as much as 8.2%, marking the steepest decline since April 2025.

The drop in share value reflects investor concern over the potential implications of the investigation. The company disclosed on Monday that it had established an independent panel of experts to examine the process by which earthquake data was selected and presented to Japan's nuclear regulatory body. This data is crucial for the planned restart of two units at the Hamaoka Nuclear Power Plant.

The market reacted swiftly to the news, signaling a loss of confidence in the utility's operational transparency and regulatory compliance. The Hamaoka plant, located in an area known for seismic activity, has been offline for an extended period, and its restart is considered vital for Chubu Electric's long-term energy supply strategy.

Chubu Electric Power Co. is a major regional utility in Japan, serving a large industrial and residential customer base. The company has been working to bring its nuclear facilities back online to reduce reliance on fossil fuels and stabilize energy costs. However, the current investigation introduces significant uncertainty and could further delay the restart of the Hamaoka plant, impacting the company's financial performance and future energy mix.

The outcome of the independent panel's investigation will be closely watched by investors and regulators alike. A finding of misconduct could lead to further regulatory scrutiny, potential fines, and a prolonged delay in the Hamaoka plant's restart, placing additional pressure on Chubu Electric's financial outlook.