Chicago-based Trading Technologies has sued trading firms before, alleging patent infringement. Four months ago, it issued an open letter to the futures industry, claiming that it is entitled to a fee of 2.5 cents per trade on each of the "big four" futures exchanges, namely Eurex US, Euronext.liffe, the Chicago Board of Trade, and the Chicago Mercantile Exchange.
Man Group plc operates in 15 countries, including the US. A spokesman told ZDNet UK that the company is confident that it is not infringing patents owned by Trading Technologies.