Chipmaker ParkerVision Inc said a federal jury in Florida found Qualcomm Inc guilty of direct and indirect infringement of the company's patents, sending ParkerVision shares up as much as 75 percent.
The court ruled that Qualcomm infringed on four patents of ParkerVision related to radio-frequency receivers and the conversion of electromagnetic signals in wireless devices and improperly used them in Qualcomm's semiconductor chips.
The trial is now in its second phase, to determine how much Qualcomm should pay as damages and whether the infringement was intentional, ParkerVision said.
According to the pre-trial statement by the two companies in September, ParkerVision is seeking damages of nearly $500 million. If found guilty of willful patent infringement the damages awarded may be increased by up to three times.
Qualcomm, the supplier of chips for Apple Inc's iPhones and Android devices, was not immediately available for comment.
Qualcomm's chips are a key component in mobile phones and tablets as they help to convert frequencies of electromagnetic signals.
ParkerVision shares were up 58 percent at $5.32 in late-afternoon trading. They hit a five-year high of $5.90. Shares of Qualcomm were down about 1 percent at $68.44.
ParkerVision, which makes chips used in wireless communications, sued Qualcomm in July 2011, saying that Qualcomm infringed seven of its patents.
In March 2013, the court denied Qualcomm's motion to dismiss the company's claims of indirect infringement.
(Reporting by Aditya Kondalamahanty and Soham Chatterjee in Bangalore; Editing by Maju Samuel)