In 2009 the European Commission opened antitrust proceedings against Thomson Reuters over possible abuse of its dominant market position in the supply of RICs - codes that identify securities and are used by financial institutions to retrieve data from Thomson Reuters' real-time feeds.

The EC argued that the firm could be abusing its dominant position in the market for these consolidated real-time datafeeds by stopping customers from using RICs for retrieving data from alternative providers and mapping them for such a purpose to alternative symbols.

In an attempt to ward off further action by the Commission, the vendor agreed to let customers license RICs for mapping purposes over a five-year period for a monthly fee based on the number of RIC symbols to be used.

However, in a speech in Copenhagen today, EU competition chief Joaquín Almunia, said that a market test of the new measures had failed to deliver a desirable outcome.

"We have now reached a critical stage in this investigation," said Almunia. "If no effective solution can be agreed upon, then we will have to draw the adequate conclusions."

The company could face fines of up to 10% of its turnover if it does not offer further concessions to users.

Thomson Reuters' rival Bloomberg has moved to make its own proprietary symbology available for free to developers and market practitioners.