Nathan Nobu Lowenstein

Nathan Nobu Lowenstein is a founding and co-Managing Partner at Lowenstein & Weatherwax LLP, a Santa Monica, California-based patent litigation boutique. His practice primarily focuses on representing patent owners in high-stakes intellectual property disputes. He handles matters across a range of complex technologies, including semiconductors, computer hardware and software, telecommunications (such as adaptive bitrate streaming), medical devices, biotechnology, digital video, and electronic commerce.

Mr. Lowenstein is notably active and highly regarded for his work in post-grant proceedings before the Patent Trial and Appeal Board (PTAB) and subsequent Federal Circuit appeals. He has served as lead counsel in hundreds of PTAB proceedings and dozens of Federal Circuit appeals. Patexia has recognized him as the #1 ranked attorney nationwide for Patent Owner Performance in PTAB proceedings for the period of July 2020 to June 2025. His firm, Lowenstein & Weatherwax, is also consistently ranked among the top-performing and most active firms representing patent owners in IPRs.

Among his notable representations, Mr. Lowenstein was lead counsel for Divx LLC in Unified Patents v. Divx LLC, an inter partes review challenging a patent related to adaptive bitrate streaming, which ultimately saw claims affirmed as unpatentable at the Federal Circuit. He also famously served as lead counsel for VLSI Technology LLC in multiple IPRs against Intel, where he secured non-institutions for twelve IPRs concerning patents that were part of a $2.18 billion jury verdict, and successfully defended IPR victories before the Federal Circuit. Other significant engagements include obtaining multiple non-institutions for Entropic Communications, MOSAID Technologies, and Cobblestone Wireless in IPRs, and affirming a complete IPR victory for Polaris Innovations, Ltd. at the Federal Circuit.

Mr. Lowenstein earned his J.D. from UCLA Law School and his B.A., with honors, from UCSC, and was admitted to practice law in California in 2005.