Mitsubishi's Singapore unit lost $90M in unauthorized oil trades — trader fired

Petro-Diamond Singapore is the Singapore-based petroleum trading unit of Mitsubishi Corporation, one of Japan's largest trading companies. In 2024, a trader responsible for crude oil derivatives for China conducted unauthorized trades that led to a loss of approximately $90 million (13.2 billion yen). The trader had been manipulating the unit's risk management system to hide the positions since January 2024.

The unauthorized trades were discovered in mid-November 2024 during a routine middle office review. Mitsubishi moved quickly: the trader was fired, reported to the police, and the company filed a formal complaint. The loss was disclosed in December 2024.

The case was notable for the speed of discovery — the trader was caught within months, not years — and for the trader's method: manipulating the risk management system itself, rather than simply exceeding limits. It showed that even a diversified trading giant with internal controls can be vulnerable to a single trader who knows how to bypass the system.

Mitsubishi caught the trader in a routine middle office review, not via automated controls, and fired him, reported to police, and disclosed the $90M loss.

The trader manipulated the risk management system, so the controls were reporting what the trader wanted rather than the true positions.

The trader was responsible for crude oil derivatives for China, a single market focus that created a blind spot in oversight.

Mitsubishi discovered the loss during a routine middle office review, not through automated controls — the trader was caught by a human check, not the system.

When a trader can manipulate the risk system, the controls are not just failing — they are lying. Mitsubishi found the loss because someone looked at the books, not because the system raised an alarm.

Mitsubishi fired the trader, reported him to the Singapore police, and filed a formal complaint. The company stated it was considering further legal action. The case highlighted the vulnerability of trading operations to insiders who understand how to bypass risk controls, and the importance of periodic manual reviews in addition to automated systems.