The decision comes as a result of accusations made by eSpeed, a Cantor Fitzgerald subsidiary, against interdealer broker Icap’s unit, Garban, that it had infringed upon its ‘580’ patent.

The jury found that Garban’s trading system was in breach of the patent licensed to eSpeed, but that this technology was not valid because the original patent application was not clear on how the bond-trading platform worked. This was laid out by Icap during the trial, who claimed that Cantor misled the US Patent Office by adding new rules to the application that were already used in the market.

This announcement is the latest in a long line of legal defeats for eSpeed. In a previous infringement suit US District Judge Kent Jordan ruled that BrokerTec, another Icap subsidiary, did not violate the patent and that Cantor was not liable to claim costs.

Scandinavian trading technology vendor OMX, who was taken to court by eSpeed over damages last year, said it would now not be tried for the case and faces no liability claims.

ESpeed itself was found guilty of infringement after an Illinois federal judge decided its dealing system contravened with patents held by Chicago-based Trading Technologies.

Michael Spencer, group CEO of ICAP, commented: We are delighted with the outcome of this case. The jury has found that eSpeed’s patent is invalid and we look forward to the judge’s decision on whether the patent was acquired by inequitable conduct.