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

But eSpeed says in a 3 January 2008 order, senior district Judge James Moran of the US District Court for the Northern District of Illinois ruled that no "reasonable" jury could find that it "wilfully infringed" TT's patented MD Trader technology.

In a statement eSpeed says it expects the judge to issue a subsequent ruling with respect to whether the $3.5 million damages awarded to TT should be reduced.

Howard Lutnick, chairman, CEO and president of eSpeed, says: "This decision clearly validates eSpeed's view that there had been no willful infringement by eSpeed in the case before the court, which addressed a minor three-year old matter involving earlier versions of eSpeed's software covering only the period of August to December 2004."

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. ESpeed says this move reinforces it view that "TT's patent claims are unsupportable".

In separate move, the Financial Times is reporting that eSpeed COO Paul Saltzman - who is also acting chief executive of a new all-electronic futures trading exchange being established in the US by a consortium of banks and trading firms - is stepping down from both posts.

Saltzman was to lead the new electronic exchange, which is based on eSpeed technology. His surprise departure is seen by some analysts as an early blow to the plans for the exchange, which is set to compete with the Chicago Mercantile Exchange (CME), says the FT.