BRUSSELS, Belgium — The European Union’s antitrust regulator is moving toward blocking the US$10 billion ($857 billion) merger between stock exchanges NYSE Euronext and Deutsche Boerse, two people close to the merger said yesterday.

The case team that has been examining the planned merger, which would create the world’s largest exchange operator, fears that the combined company would have an overly dominant position in the trading and clearing of exchange-traded derivatives in Europe, said one of the people.

Because of their concerns, the EU’s Competition Commissioner Joaquin Almunia is set to recommend blocking the deal at a meeting with his fellow Commissioners on February 1, the person said.

A majority of commissioners has to back the prohibition of the merger and a final decision has to come by February 9, at the latest.

A second person close to the merger confirmed that “it looks like they (the European Commission) is working toward a prohibition.”

Both people requested anonymity because the process is confidential.

The negative opinion from the case team will set off several weeks of intense lobbying in which Deutsche Boerse and NYSE Euronext will try to convince other commissioners to advocate for the merger, which they say will strengthen Europe’s position in global financial markets and cut costs for banks and other financial firms using their trading and clearing services.

Opponents of the deal, such as the London Stock Exchange Group PLC and Nasdaq, meanwhile, will push for the deal to be blocked, arguing that it threatens to destroy other companies trying to move into the trading and clearing of derivatives.

Derivatives are complex financial products that allow investors to bet on developments in areas such as interest rates, stock indexes or commodity prices.