Shares of Wi-LAN were down almost 12 percent at C$3.46 in Toronto.
The Canadian owner of patents for technology used in mobile phones has to date signed license and settlement agreements with both HTC and Sierra Wireless to resolve the case.
But the suit against remaining defendant Apple is being tried in the US District Court for the Southern District of California, and earlier this year, Wi-LAN moved for summary judgement on invalidity claims while Apple moved for summary judgement on both invalidity and non-infringement defenses.
The intellectual property licensing firm is currently reviewing the ruling, it said, with the case remaining before the courts. The company also has an additional suit in the same district involving Apple, related to the infringement of five LTE-related patents.
Since refocusing the Ottawa-based company on intellectual property licensing in mid-2006, Wi-LAN has signed more than 270 license agreements worth between $725 and $750 million, and has a portfolio of more than 3,000 issued or pending patents.