The jury awarded US$388 million in the case, double the estimated damages caused by infringing the patent.

Uniloc makes software that prevents the creation, distribution and use of unauthorized copies of software. The company had accused Microsoft of infringing on a patent in the anti-piracy software registration system Microsoft uses as part of its product activation system.

The Wednesday decision is a reversal of an earlier judgement in which the U.S. District Court for the District of Rhode Island found in favor of Microsoft that no infringement had occurred. Last August, the U.S. Court of Appeals remanded the matter back to the District Court for a trial.

Neither Uniloc nor Microsoft could immediately be reached for comment.