BRUSSELS (Reuters) - A European Union court upheld on Monday the European Commission's decision in 2012 to block a planned merger of Deutsche Boerse (>> Deutsche Boerse AG) and NYSE Euronext.

The Commission blocked the deal to create the world's biggest stock exchange because it said it would have created a "near monopoly" in European financial derivatives.

The deal, one of a number to be challenged by international regulators, was scrapped. Indeed, at the end of 2012, Intercontinental Exchange (ICE) (>> Intercontinental Exchange Inc) acquired NYSE Euronext, with Euronext (>> Euronext) subsequently spun off and floated.

Deutsche Boerse nevertheless contested the Commission's decision on three issues.

Firstly, it said the Commission should have considered that over-the-counter (OTC) trade compete with exchange-traded derivatives (ETDs). The merged group would have had a huge share of the latter, but ETDs only make up a small part of overall derivatives trades.

It also said that the Commission did not adequately consider that some merger efficiencies could have benefited customers, counteracting the potential negative impact on competition.

Thirdly, it said that the Commission had failed properly to assess the remedies offered by the parties

The General Court, the EU's second-highest judicial authority, said on Monday that the Commission had not made legal errors or mistakes in its assessment in its definition of the relevant market.

The court also rejected Deutsche Boerse's argument that a merger could have created efficiencies benefiting customers and that concessions made by the companies were sufficient.

Deutsche Boerse said it still believed the Commission had applied a market definition that was too narrow, adding it would consider whether to appeal.

An appeal, limited to points of law, can be brought before the Court of Justice within two months.

(Reporting By Philip Blenkinsop and Jonathan Gould; editing by Robert-Jan Bartunek/Hugh Lawson)

Stocks treated in this article : Deutsche Boerse AG, Intercontinental Exchange Inc, Euronext