By Jethro Mullen and Daniel Shane, CNN Business

(CNN) -- Questions over Nissan's reporting of executive pay have spread to the United States.

The Japanese automaker said Monday that it has received an inquiry from the US Securities and Exchange Commission and is "cooperating fully."

Nissan made the comment in relation to a Bloomberg report, which said the American regulator is looking into whether the company accurately disclosed its executive pay in the United States.

Nissan — whose stock trades in both Tokyo and New York — declined to provide further details. The SEC didn't immediately respond to a request for comment outside regular office hours.

An SEC probe could prove costly for Nissan. The agency has the power to impose financial penalties on companies it deems to have broken US securities rules.

Nissan shares in Tokyo, which had been in positive territory earlier in the day, fell following the Bloomberg report, closing down 0.8%.

The news follows the recent indictment in Japan of former Nissan boss Carlos Ghosn on charges that include understating his income in Japanese securities filings by tens of millions of dollars over an eight-year period. Nissan and Greg Kelly, a former top executive at the company, have also been indicted in the case.

Ghosn and Kelly have denied any wrongdoing.

Nissan, which is cooperating with Japanese prosecutors, said following its indictment that it "will continue its efforts to strengthen its governance and compliance, including making accurate disclosures of corporate information."

Nissan and Mitsubishi Motors both fired Ghosn, one of the auto industry's most prominent figures, as chairman soon after his arrest in November. He resigned as chairman and CEO of France's Renault last week after the French government withdrew its support for him.

Ghosn brought Nissan, Renault and Mitsubishi together to form the world's biggest carmaking alliance, which produces more than 10 million vehicles a year. His downfall has strained but not broken the ties between the companies.

The former auto executive has spent more than two months in jail since his arrest in Tokyo. In a court appearance earlier this month, he said he had been unfairly detained on "meritless and unsubstantiated accusations."