But Intellectual Ventures paid only $750,000 for the patent.
Intellectual Ventures is demanding $310m from Symantec and Trend Micro for using its patented technology through the end of 2012, despite spending just $750,000 on the patent.
IV told a court in Delaware that the figure represents reasonable compensation given how broadly the products manufactured by both firms rely on the technology, which helps detect malware in digital content.
But both Symantec and Trend Micro are defending and proceeding with a legal argument asking the judge to bar IV from requesting such large compensation based on the idea that a patent acquired for so little money could not be worth the requested amount.
They also argue that Symantec and Trend Micro did not breach patents of IV, Reuters reported.
Lawyers of the firms also argued that the law bars IV from demanding a high royalty.
Both firms including two other software security companies were sued by IV in 2010, when the company argued that a court case was an inefficient way to establish patent royalties and favoured negotiating licensing deals for its patent portfolio.