A Morgan Stanley trader is leaving the firm after racking up tens of millions of dollars in losses as a bout of market turmoil makes and breaks trading books across Wall Street.

Hamza El Hassani, who traded dividends in the New York-based bank’s equities division, will be departing after transactions he oversaw went awry, according to people with knowledge of the matter. The losses tied to him were less than $50 million, one of the people said.

El Hassani didn’t respond to a message seeking comment, and a representative for Morgan Stanley declined to comment.

Russia’s invasion of Ukraine has rocked global markets and spiraled across asset classes, catching some traders off guard and testing their hedges. An onslaught of international sanctions has severed correlations between a number of products that normally move in sync, derailing bets that were otherwise seen as safe. Heavy losses aren’t unusual in such trading conditions and they don’t always prompt separations from firms. 

Trading dividends is a niche of Wall Street financial engineering that lets investors bet on the dividend flows from a basket of shares or even single companies. Market uncertainty in recent weeks has hit dividend books across the street, opening up those trading desks to unexpected losses, one person said.

The bank’s equity-derivatives unit sits within its equities business that also deals in common stocks and provides services to hedge funds. At Morgan Stanley, that business is normally seen as a market leader but fell behind Goldman Sachs Sachs Group Inc. in the final tally last year due to losses tied to Bill Hwang’s Archegos Capital Management.

El Hassani had been with Morgan Stanley since 2017, according to brokerage industry records. He previously worked at Deutsche Bank AG and Societe Generale SA.

Morgan Stanley is separately facing heightened public attention in another area of its operations: its handling of large stock transactions known as block trades. The bank acknowledged in a regulatory filing late last month that U.S. authorities are investigating various aspects of that business. It hasn’t been accused of any wrongdoing.

--With assistance from Gillian Tan and Matt Turner.

This article was provided by Bloomberg News.