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

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.