Nissan said it is “co-operating” with an inquiry by US regulators, following reports that the carmaker is being investigated over executive pay disclosures.
On Monday, US media reported the Securities and Exchange Commission (SEC) had launched a probe into Nissan.
The carmaker did not give further details about the inquiry.
It comes as the firm’s former chairman Carlos Ghosn faces charges of financial misconduct in Japan.
“I can confirm that we have received an inquiry from the SEC, and are cooperating fully. We cannot provide further details,” a spokesperson for Nissan said.
US media reported the SEC is investigating whether the Nissan maintained adequate controls to prevent improper payments.
The Japanese carmaker has accused Mr Ghosn of financial misconduct.
Last month, it said an internal investigation had found Mr Ghosn received “improper payments” totalling €7.8m ($8.9m; £6.9m) from a joint venture between the carmaker and Mitsubishi.
The 64-year-old was first arrested on 19 November and remains in detention in Tokyo, where he faces charges of financial misconduct and breach of trust.
He has denied the accusations.