Patent claims filed by Non-Practicing Entities (NPEs) in the United States are emerging as a risk for Korean chipmakers, as Washington is increasingly leaning in favor of patent holders, forcing companies to incur greater legal costs by defending themselves against so-called “patent trolls.” The U.S. Patent Trial and Appeal Board (PTAB) on Friday (local time) rejected two petitions filed by SK hynix in August 2025 seeking to invalidate patents held by Advanced Memory Technologies, an NPE which has been staging patent battles against a series of Korean IT companies. PTAB has put SK hynix’s two petitions, known as inter partes reviews (IPRs), into “Not Instituted” status, meaning the challenges were rejected without a review process. The board had rejected three other SK hynix IPRs in December. Advanced Memory Technologies filed a patent infringement suit with the U.S. District Court for the Eastern District of Texas in December 2024, claiming that SK hynix had infringed on five of its patents for dynamic random access memory and flash memory technologies. IPR was introduced in 2