The Commission says it will investigate Thomson Reuters' practices in the area of real-time market datafeeds, and in particular "whether customers or competitors are prevented from translating Reuters Instrument Codes (RICs) to alternative identification codes of other datafeed suppliers (so-called 'mapping') to the detriment of competition".

Without the possibility of such mapping, customers may potentially be "locked"-in to working with Thomson Reuters, says the Commission, because replacing RICs by reconfiguring or by rewriting their software applications can be a long and costly procedure.

In a research note, Citi analyst Thomas Singlehurst questiona the validity of the EC probe and asks why the issue wasn't aired during the Thomson Reuters merger inquest: "It is not at all clear that there is a case to be investigated. RICs are Reuters' own codification system. Technically it is their own (intellectual property) just as the Bloomberg codes are the property of Bloomberg). This investigation comes just 18 months after the EU itself approved the merger of Thomson and Reuters and it seems strange that, if this was an issue, it wasn't raised at that stage,"

The opening of proceedings against Thomson Reuters follows a similar move by the EC earlier this year to assess whether Standard & Poor's abused its dominant market position by forcing financial firms to pay for the use of US securities numbering codes when accessing data from third party vendors.

That investigation is ongoing.

The latest probe comes at an apposite moment, just weeks after rival data vendor Bloomberg turned the securities numbering business on its head by launching a new Website where industry participants can freely search for, access and re-use identifiers developed for the Bloomberg Professional terminal and enterprise data products.