Apple could be forced to pay significant damages after a US jury found that it used technology in its chips owned by the Wisconsin Alumni Research Foundation (WARF) without permission.
The judge dealing with the case estimated that the manufacturer could be forced to pay up to $862m for the patent infringement which relates to a 1998 processor efficiency patent.
The Research Foundation first sued the Californian manufacturer in January 2014. The action relates to Apple's A7, A8 and A8X processors which are found in the iPhone 5s, 6 and 6 Plus, as well as a number of iPad’s.
Apple deny that their products breach the patent, which was previously used by WARF to sue Intel.
The Research Foundation is also pursuing legal action against Apple regarding technology on the latest chips; the A9 and A9X which feature in the iPhone 6S, 6S Plus and iPad Pro.
Apple has been locked in a number of patent disputes in recent years most notably with fierce rival Samsung.
Read our analysis of why manufacturers frequently take each other to court on these issues here.
Mobile has contacted both Apple and WARF and is awaiting a response.