The suit was filed yesterday in the United States District Court by TT, alleging that Patsystems has infringed certain of TT's patents.

In a brief statement, Patsystems says the lawsuit will be disposed of once the settlement has been approved by the Court.

It goes on to say: "The directors believe that this agreement is in the best interests of Patsystems and they further believe that it will have no material financial impact on the company."

Further details will be forthcoming once the claim is settled.

Patsystems is the sixth firm to be accused of patent infringement by TT. The Chicago firm has claims outstanding against UK hedge fund manager Man Group, futures commission merchant Refco and bond trading network eSpeed. Chicago brokers Kingstree Trading and Goldenberg Hehmeyer both agreed an out-of-court settlement with TT within days of being sued by the vendor last year.

In its financial results for 2004, Patsystems noted that uncertainty arising from the Trading Technologies patents issue was unsettling the market, resulting in the delay of at least two major prospective projects.

Shares in the vendor moved up 3.7% or 0.5 pence to 14 pence on news of the settlement.