Morgan Stanley has bought Deutsche Bank’s bulk commodities trading book dealing in coal, iron ore and freight forward contracts to expand in commodities derivatives, a source familiar with the matter said on Thursday.

The deal marks an apparent return to iron ore for the Wall Street bank, which exited the market by last year, and an expansion in coal and freight.

The acquisition will broaden Morgan Stanley’s customer base, making it the counterparty for structured transactions with a wide range of end-users.

Expansion of its derivatives presence comes at a critical time for the bank, whose physical business has drawn intense scrutiny from U.S. regulators and politicians concerned about the involvement of Wall Street banks in physical commodity markets.

Facing growing pressure and tighter regulations, the bank is offloading its interest in Transmontaigne, a U.S.-based oil storage and transport company, and selling its physical oil business to Russian gas producer Rosneft.

The size of the book is not known, although Deutsche was one of the pioneers of iron ore swaps trading in 2008.

Spot trading in iron ore, the world’s most traded commodity by volume after oil, and in coal have ballooned in recent years and both are closely linked to the dry freight sector.

The bulk commodities book is one of 17 put up for sale by Deutsche, Germany’s largest bank and one of the top-five financial participants in commodities, as part of its decision to exit commodities trading because of toughening regulations and diminished profits.

Citigroup bought the German bank’s U.S. power trading books, and EDF Trading purchased its European power and gas books.

The sale was first reported by financial industry newsletter SparkSpread. The transaction occurred last week, it said.