In October TT claimed victory in the long-running lawsuit after a jury ordered the Cantor Fitzgerald unit to pay it $3.5 million in damages.

But in a statement released last week, eSpeed said that in a 3 January 2008 order, senior district Judge James Moran of the US District Court for the Northern District of Illinois "agreed with eSpeed's motion for a judgement as a matter of law, overturning the jury's October 10 2007 verdict that certain versions of eSpeed's futures-trading software had infringed TT's patents".

ESpeed says the judge ruled that no "reasonable" jury could find that it "wilfully infringed" TT's patented MD Trader technology.

But in its own statement TT disputes the statement, claiming that on the same day in a separate decision the judge denied eSpeed's motion to set aside the jury's verdict of infringement.

In court papers supplied by TT, a minute entry before Judge James Moran, says: "Defendant eSpeed's Combined Motion for Judgement as a Matter of Law that the asserted claims are invalid based on obviousness, anticipation, prior sale, and that the claims have a priority date of June 9, 2000 and have not been infringed [1099] is denied. We agree with defendants that this motion is timely and proper and is not waived. However, we decline to vacate the jury's findings on these issues."

TT says that the judge only overruled the jury's finding of "willfulness" and this is relevant to whether the $3.5 million damages awarded for four to five months of infringement should be increased.

The vendor insists that the jury's finding that eSpeed is liable for patent infringement stands.

The lawsuit is one of more than a dozen filed by TT against brokerages and other vendors over patents related to its MD Trader product, the order-entry screen incorporated in TT's X_Trader software. Unlike eSpeed, the majority have settled with TT out of court.

However in August the US Patent and Trademark Office said it would re-examine and re-evaluate patents held by TT relating to the vendor's order entry system.