NPEs (Non-Practicing Entity) remain a dominant force in the US patent litigation landscape. Their core strategy is straightforward: to acquire or license patents from practicing companies and enforce them by identifying potential licensors and infringers.
Sometimes, the practicing companies sell the patents that no longer align with their current business focus. At other times, the technologies have become obsolete, and the IP holds no long-term strategic value.
NPEs, on the other hand, excel in finding overlooked value in patents, even in those that have recently expired. In fact, they often find so much potential in the expired patent that they actively seek to acquire it.
At first glance, it doesn’t make sense. Why would anyone pay money for a dead patent? But our analysis of the 2024 US patent litigation landscape showed otherwise.
In 2024, one out of every four patent lawsuits in the US was filed by a Non-Practicing Entity (NPE)
Amid the usual mix of operating companies locked in infringement battles, one trend stood out: a noticeable rise in lawsuits filed by NPEs.
Patent reassignment data from the past three years showed the same pattern: NPE (Non Practicing Entity) litigation continues to rise. And, they’ve been highly strategic. They target industry giants in highly competitive domains, such as telecommunications, semiconductors, and cameras.
NPEs Heavily Litigated Telecom Sector from 2022-25
| Domain | Number of Litigations by NPEs (2022-25) |
| Telecommunication | 42 |
| Display Technology & Structure | 27 |
| Semiconductor | 23 |
| Data Processing | 17 |
| Privacy and Security | 16 |
| Network & Communication | 13 |
| Multimedia and Broadcasting | 12 |
| UI/UX | 9 |
| Data Management & Storage | 8 |
| Camera and Imaging Systems | 6 |
| Navigation and Mapping | 4 |
| Medical Devices & Imaging Systems | 3 |
| Voltage & Power Management | 3 |
| Automation | 3 |
| Sensor | 2 |
| Software and Application | 1 |
| Electric Circuits & Apparatus | 1 |
| Cloud Computing | 1 |
| Vehicle Controlling System | 1 |
| AR/VR | 1 |
Businesses operating in the sectors that are hotbeds for litigation must track recently acquired patents by NPEs to avoid potential litigation and explore timely licensing opportunities. This is because NPEs aggressively file lawsuits after patent acquisitions.
In 2016, Uniloc launched a litigation campaign against a long list of 17 defendants, including companies such as Apple, Facebook, and Sony, for infringing their four patents related to Voice over IP technology. Interestingly, the first lawsuit was filed against Samsung on 16 July 2016, just one week after Uniloc acquired the patents from Empire IP LLC.
Access the full list of patents acquired by NPEs in 2024 by filling out the form below.
Patent Armory Emerged as the Most Litigious NPE With 2x More Lawsuits Than Its Closest Competitor
Here are the top 10 NPEs and the technology areas they targeted most heavily:
| S. No. | NPE | Number of patents acquired | No. of Companies litigated | Technology Area |
| 1 | Patent Armory Inc | 34 | 879 | Data Processing, Network & Communication, Telecommunication |
| 2 | Intellectual Ventures | 1054 | 228 | Telecommunication, Network & Communication, Sensor, Multimedia & Broadcasting, Data Management & Storage, and More… |
| 3 | Iot Innovations LLC | 48 | 223 | Data Processing, Telecommunication, UI/UX, Privacy & Security, Software & Application, and More… |
| 4 | Optimorphix Inc | 64 | 128 | Telecommunication, Multimedia & Broadcasting, Privacy & Security, Network & Communication, UI/UX, and More… |
| 5 | Daedalus Prime LLC | 135 | 71 | Voltage & Power Management, Data Management & Storage, Semiconductor, Data Processing, Privacy & Security, and More… |
| 6 | Freedom Patents LLC | 3 | 69 | Telecommunication |
| 7 | Authentixx LLC | 4 | 58 | Privacy And Security |
| 8 | Bx Led LLC | 29 | 57 | Display Technology & Structure |
| 9 | Semiled Innovations LLLC | 8 | 46 | Display Technology & Structure, Semiconductor |
| 10 | Light Guide Innovations LLC | 29 | 45 | Camera & Imaging Systems, Display Technology & Structure |
Despite its litigation dominance, Patent Armory wasn’t the biggest acquirer of patents. That title belonged to Mimir IP LLC. In a massive transaction in March 2024, SK Hynix Inc.—a global semiconductor giant—transferred 1,726 patents to Mimir IP LLC.
This led us to investigate how NPEs are building their portfolios. From where are they acquiring patents?
Most of these patents were acquired directly from operating businesses
In 2024, more than 30 businesses transferred patents to NPEs, but a few names stood out.
| S. No | Company | Patent Count | NPE |
| 1 | Sk Hynix Inc | 1726 | Mimirip Llc |
| 2 | Mind Fusion Llc | 867 | Intellectual Ventures Musicqubed Innovations Llc Gamehancement Llc |
| 3 | Auo Corporation | 213 | Optronic Sciences Llc |
| 4 | Huawei | 166 | Godo Kaisha Ip |
| 5 | Intel | 135 | Daedalus Prime Llc |
| 6 | Telecommunications Systems | 63 | Artax Llc |
| 7 | Nuvoton Technology | 57 | Advanced Integrated Circuit Process Llc |
| 8 | Epson | 32 | 138 East Lcd Advancements Limited |
| 9 | Suzhou Lekin Semiconductor | 29 | Light Guide Innovations Llc |
| 10 | Bridgelux Inc | 29 | Bx Led Llc |
Struggling to offload patents? Get the complete list of NPEs and their specialized technology domains to identify the right buyers.
NPEs Acquired Over 700 Patents in the Semiconductor Domain
Semiconductor patents topped the reassignment list with 760 transfers, followed closely by those related to Data Management and Storage. These areas are foundational to modern technology, and often tough to design around without risk of infringement.
But here’s the twist: We noted that many of these patents were expired. Which brings us back to why were NPEs acquiring patents that seemed no longer enforceable.
NPEs Target Past Infringers Using Expired Patents (Dead Patents Acquisition)
Once the patent expires, the patent holder’s exclusive rights are gone. The holder can no longer sue companies for using and selling products covered by the expired patent. However, if the infringement happened when the patent was alive, the patent holder can sue other parties for damages accrued over the patent’s active period.
But there’s a time limit: Due to the six-year statute of limitations (35 U.S.C. § 286), you can only sue for damages from infringement that happened within the 6 years before you file the lawsuit.
If you file a lawsuit in 2025 for a patent that expired in 2021, the case can still proceed. You may claim damages for infringement that occurred between 2019 and 2021.
Uniloc exercised this right and enforced US5490216A even after the patent expired in September 2013. The NPE filed lawsuits against more than 23 companies up until June 2014. While the patent had expired, Uniloc was still within its legal window to seek damages for any infringement that occurred during the patent’s active life, thanks to the six-year statute of limitations under 35 U.S.C. § 286. US5490216 completed its full 20-year term and generated millions for Uniloc through royalty payments. However, in 2016, the patent was ultimately invalidated following an Inter Partes Review initiated by Sega of America and four other entities. Had it not been for this invalidation, Uniloc’s wave of post-expiry litigation likely would have continued beyond 2014.
Author’s Note: There is an exception. If you misled the infringer into thinking you wouldn’t sue (equitable estoppel), you might not get anything, even within the 6-year window.
Rabicoff Law represented the most litigious NPEs
From 2022 to 2025, over 350 law firms took part in NPE-related cases. But a few dominated the landscape.
Rabicoff Law led the pack, representing NPEs in a staggering 486 cases—more than double the next most active firm, Ramey LLP.
Here’s a breakdown of the top 10 law firms representing NPEs during this period:
| S. No. | Law Firm | Count of Cases |
| 1 | Rabicoff Law | 486 |
| 2 | Ramey LLP | 197 |
| 3 | Garibian Law Offices PC | 89 |
| 4 | Rozier Hardt McDonough | 80 |
| 5 | Garteiser Honea PC | 70 |
| 6 | Russ August & Kabat | 53 |
| 7 | Direction IP Law | 50 |
| 8 | Fabricant LLP | 49 |
| 9 | Nelson Bumgardner Conroy PC | 34 |
| 10 | McKool Smith | 32 |
