SK hynix sues Longhorn IP again, alleging repeated patent demands through affiliates

Context: SK hynix and Longhorn IP affiliates were previously involved in patent litigation that ended with licensing agreements in October 2022. More recently, Longhorn was named in a separate declaratory judgment action filed by Lenovo and Motorola Mobility in July 2026, in which Lenovo cited SK hynix’s earlier dispute as further evidence of allegedly similar patent assertion practices.

What’s new: SK hynix yesterday sued Longhorn IP and Mago Barca IP in the United States District Court for the Northern District of California, seeking declarations of noninfringement of eight former TSMC patents and the invalidity of seven of them. SK hynix disputes allegations that its high-bandwidth memory (HBM) and dynamic random-access memory (DRAM) products infringe the patents and claims that Longhorn and Mago Barca continued demanding a license at unreasonable rates despite repeated negotiations.

Direct impact: SK hynix is seeking to resolve the infringement allegations through litigation after nearly a year of unsuccessful licensing negotiations. A favorable ruling could clear its accused memory products of infringement claims and invalidate seven patents, potentially undermining Mago Barca’s ability to enforce them against other companies.

Wider ramifications: The case highlights the potential for renewed patent disputes when licensing companies acquire additional portfolios and assert them against existing licensees through separate affiliates. Together with Lenovo’s recent lawsuit, it highlights growing legal challenges to Longhorn’s patent assertion practices in the semiconductor industry.