About
Provided by Lowenstein & Weatherwax LLP
Lowenstein & Weatherwax LLP is a nationally recognized patent litigation boutique focused on representing patent owners in high-stakes PTAB proceedings, patent reexaminations, related Federal Circuit appeals, and district court patent litigation. The firm is particularly known for patent owner-side inter partes review defense, post-grant strategy, institution-stage advocacy, expert-driven technical analysis, its written and oral advocacy, and appellate work arising from complex patent validity disputes.
L&W has litigated more than 400+ IPR/CBM proceedings and nearly 80 CAFC appeals, often against many of the country’s largest law firms and technology companies. Its matters span semiconductors, computer hardware and software, telecommunications, medical devices, biotechnology, digital video, electronic commerce, and other technically complex fields.
The firm’s PTAB work has been repeatedly recognized by Patexia. Patexia ranked founding partner Nathan Lowenstein #1 in Patent Owner Performance among 5,650 PTAB practitioners nationwide for the July 2020–June 2025 period. Patexia also identified Lowenstein & Weatherwax as the top-performing IPR firm in the country for 2013–2018, and as the sixth most active and sixth best-performing firm representing patent owners for 2020–2025. The firm combines boutique efficiency with deep PTAB, appellate, and trial-court experience, giving patent owners a focused litigation team built for technically demanding, high-value patent disputes.