(Bloomberg) — Mitsubishi Corp. (8058.T) said it had suffered a loss of more than $90 million in China after uncovering suspected fraud by one of its copper traders.

Most Read from Bloomberg

• As Wars Rage, Cities Face a Dark New Era of Urban Destruction

• Riyadh Metro Partially Opens in Bid to Ease City’s Traffic Jams

The loss is the latest in a string of recent cases of alleged wrongdoing to hit major commodity trading houses, highlighting the risk that individual traders who handle billions of dollars in commodities may seek to enrich themselves at the expense of their own companies.

In October, Trafigura Group said it was facing a $1.1 billion hit in Mongolia involving suspected wrongdoing by its own employees. While the scale of Mitsubishi’s loss is considerably smaller, it has nonetheless sent a chill through the giant Japanese trading house.

Mitsubishi dismissed Gong Huayong, a Shanghai-based copper trader at one of its China units, after finding that he had made unauthorized trades with local companies, including some that were related to him, according to people familiar with the matter.

The company had disclosed a loss of 13.8 billion yen ($92.2 million) in its most recent quarterly results, citing “a loss in its Chinese trading business,” without further explanation. A spokesperson for the company said on Wednesday that figure was attributable to Gong, confirming Bloomberg’s earlier report, but added no further losses would be booked in connection with the rogue trades.

Mitsubishi Corp. shares slid as much as 2.1% on the news, though they later recovered ground to trade down 0.7% at around 1:30 p.m. Singapore time.

The spokesperson, who also confirmed that Gong had been dismissed, said a criminal complaint had been filed. The company said it would cooperate fully with authorities, but declined to comment further on what it said was now a criminal matter.

Calls and messages to Gong’s mobile phone did not go through, and an email inquiry to his company address was rejected. Several traders in China, who used to have business connections with Gong, said they also could not reach him. These traders asked to be not named due to the sensitivity of the case.

Mitsubishi began investigating Gong’s trades earlier this year, after some customers in its copper business failed to settle trades or defaulted on payments that were due, said the people, who asked not to be identified as they aren’t authorized to speak publicly.

The Japanese company found that Gong, a Chinese national who worked as a trading manager at Mitsubishi Corporation RtM China Ltd., had caused Mitsubishi to allow certain local companies to defer payment for copper concentrate and refined copper, the people said. In some cases Mitsubishi had not approved the companies as counterparties, and in some cases the companies had personal ties to Gong.