Carlos Ghosn, ousted former chairman of Nissan Motor Co., is suspected of shifting some 1.7 billion yen ($15 million) of personal investment losses to the automaker in 2008, adding to the financial misconduct allegations against him, sources close to the matter said Tuesday.

Japan's Securities and Exchange Surveillance Commission was aware of the alleged misconduct in relation to Ghosn's derivatives trading and notified the bank involved in the transaction of the possibility that he had committed an aggravated breach of trust, the sources said.

Nissan shouldered the losses incurred amid the global financial crisis in 2008 after Ghosn could not secure sufficient collateral, they said.

Ghosn was arrested by Tokyo prosecutors last week for allegedly violating Japan's Financial Instruments and Exchange Act by underreporting his remuneration by around 5 billion yen over five years to March 2015 even though he received some 10 billion yen in the period.

The prosecutors are also considering building a case against him for allegedly underreporting a further 3 billion yen in remuneration received over three years from April 2015.

The 64-year-old has denied intending to falsify the financial statements, but admitted that he did not include in the documents part of the remuneration he was set to receive when he retires because the "payments have not been settled," according to the sources.

The sources said Ghosn believed he should receive some 2 billion yen annually as remuneration, but instructed his close aide Greg Kelly, a former Nissan representative director who was arrested along with him, for alleged conspiracy, to submit that he earned 1 billion yen a year in securities reports.

The move was apparently aimed at fending off criticisms from shareholders and investors that the amount is too high. Ghosn intended to receive the remaining 1 billion yen after retirement, according to the sources.

Kelly, who also denies there was a need to list the remuneration, has told investigators that the payment was intended to keep Ghosn tied to Nissan even after his retirement, the sources said.

Other sources have said earlier that Ghosn has made a document that shows Nissan had agreed on the post-retirement payment, which was shared with a limited number of senior officials, including Kelly. The prosecutors have seized the paper.

Ghosn told investigators that he has let Kelly be in charge of what to write in the financial statements and that he heard from Kelly the reports' contents were legitimate.

The financial instruments law requires that remuneration be disclosed in a securities report when it is fixed even if the actual payout is planned in the future.

Ghosn used luxury residences outside Japan, apparently purchased by a firm set up by Nissan's Amsterdam-based subsidiary, for free, the sources said.

The subsidiary, Zi-A Capital BV, has a wholly-owned unit in the tax-haven British Virgin Islands through which it is believed to have bought upscale homes, including those in Rio de Janeiro and Beirut, for use by the Brazilian-born chairman with French and Lebanon citizenship.

The prosecutors suspect that Kelly, 62, sought to hide the flow of Nissan funds by setting up the sub-subsidiary in a tax-haven territory, they said.

Among other allegations, Ghosn is also suspected of having used one of Nissan's leased business jets for private trips, including to countries where the automaker has no major bases, the sources said.

At a time his luxurious home was renovated four or five years ago in Beirut, Ghosn was seen visiting the site almost every month using the jet dedicated to him, they said. The plane, manufactured by Gulfstream Aerospace Corp. and bearing the sign "N155AN," is a high-end model priced at billions of yen.