NetLens Technologies v. Microsoft — Licensee Can Sue, but Not for Pre-License Infringement

Background

NetLens Technologies accused Microsoft’s Azure platform of infringing four patents concerning virtualization, cloud monitoring, and related network technology. Three of the patents originated with South Korea’s Electronics and Telecommunications Research Institute, which granted an exclusive license to Hipe IP Inc.; Hipe later transferred its contractual position to NetLens. Microsoft moved to dismiss the claims involving those three patents, arguing that NetLens lacked the rights needed to sue and, alternatively, could not seek damages for infringement predating its license.

The Court’s Holding

The court held that NetLens may pursue infringement claims because the license transferred all substantial rights in the three challenged patents. The agreement’s grant was not merely a label: neither ETRI nor Hipe expressly retained rights that materially limited NetLens’s control, and the agreement authorized patent practice, licensing, and litigation.

But NetLens could not seek relief for infringement before June 19, 2025. Federal Circuit law requires an assignment to expressly transfer the right to sue for past infringement. Language conveying “all rights, title, and interest,” a general litigation right, and authority to license or collect fees for past periods did not expressly assign accrued infringement claims. The court therefore dismissed the pre-license portions of counts II, III, and IV without prejudice while allowing the remaining claims to proceed.

Key Takeaways

• An exclusive licensee can sue in its own name when the agreement transfers all substantial patent rights and does not leave the licensor with meaningful control.
• A transfer of broad patent rights does not automatically include accrued claims for earlier infringement.
• Parties that intend to transfer past-damages claims should say expressly that the assignee receives the right to sue for infringement occurring before the transfer date.
• NetLens’s case continues, but its recoverable period for three patents begins no earlier than June 19, 2025 unless it can plead facts establishing an express transfer of earlier claims.

Why It Matters

The ruling illustrates two distinct drafting questions in patent transfers. A license can be broad enough to confer statutory standing while still being too narrow to carry previously accrued causes of action. Patent owners and monetization entities therefore need separate, explicit language addressing both present enforcement authority and the right to recover for historical infringement.

Surfaced via Law360 IP.