6-min read
Last updated: 10 June 2026
Data in this report is sourced from IP Pilot and is accurate as of May 2026 and is based on the number of patent filings first published between 2021 and 2025. Because patent data may be subject to reporting delays in public databases, figures may fluctuate over time.
Patent filings in the United States demonstrated robust, if gradually declining, activity between 2021 and 2025, reflecting both the enduring strength of the world’s largest IP market and broader macroeconomic pressures that reshaped filing volumes across the period. Over these five years, the USPTO received hundreds of thousands of applications handled by more than a thousand law firms. The top 25 firms alone accounted for a substantial share of all filings (498,451 or 22%), underscoring the concentration of patent prosecution activity among a relatively small group of specialist and full-service IP practices.
The data used in this report was sourced from IP Pilot, an IP intelligence platform for law firms that analyzes agents, clients, and their relationships. This report covers patent prosecution activity at the USPTO from 2021 to 2025, including total filing volumes, annual trends, foreign client share, and PCT filing share for the leading top 50 firms.
Rank: Top 25 Patent Prosecution Firms in the US
United States: Number of Patent Applications and Shares of Foreign Filings per Firm
At the forefront of the US IP landscape is Fish & Richardson, which filed 42,093 applications over the five-year period — more than any other firm. Sughrue Mion, PLLC follows in second place with 34,998 filings, distinguished by an exceptionally high foreign client share of 82%, reflecting its prominence as a preferred US entry point for international applicants. Foley & Lardner LLP rounds out the top three with 31,328 filings.
Firms such as Kilpatrick Townsend & Stockton LLP (26,224), Knobbe, Martens, Olson & Bear, LLP (24,986), and Harness, Dickey & Pierce (23,663) demonstrate that large, diversified practices remain highly competitive in pure volume.
Firms with notably high foreign client exposure — including Oliff PLC (91%), Xsensus LLP (90%), Birch, Stewart, Kolasch & Birch, LLP (82%), and Oblon, McClelland, Maier & Neustadt, LLP (78%) — reflect the degree to which the US prosecution market is driven by inbound international work, particularly from East Asia.
By contrast, firms such as Schwegman, Lundberg & Woessner, P.A. (8% foreign share), Wilson Sonsini Goodrich & Rosati (8%), and Patterson + Sheridan (9%) serve predominantly domestic US-origin clients, pointing to distinct market positioning strategies within the top tier.
Filing Trends Over Time: Resilience and Realignment in the US Market
The 2021–2025 period was shaped by a series of global forces — post-pandemic normalization, rising interest rates, tighter venture capital conditions, and a re-evaluation of patent portfolio strategies among major technology companies. Against that backdrop, the performance of the leading US prosecution firms reflects not simply volume figures, but the underlying resilience of a mature and deeply established market.
Several key themes emerge from the data:
- The market demonstrated structural depth. Even as overall filing volumes moderated from the peaks seen in 2021 and 2022, the top 50 firms collectively handled hundreds of thousands of applications across the period — a foundation that speaks to the enduring health of US innovation activity.
The broader picture is one of market recalibration rather than retreat. The USPTO remains one of the world's primary patent filing destinations, and the law firms that serve it are adapting — investing in international referral networks, PCT infrastructure, and sector-specific expertise to position themselves for the next growth cycle.
Noteworthy Law Firm Trends
While aggregate five-year figures tell one story, the year-on-year trajectories reveal sharper dynamics beneath the surface:
- Xsensus LLP, ranked 27th overall, recorded the strongest growth trajectory of any top-30 firm — growing from 1,955 filings in 2021 to a peak of 2,975 in 2024. Its high foreign and PCT share (both 90% and 69% respectively) suggests a focused strategy around international prosecution work that insulated it from domestic market pressures.
- Sughrue Mion, PLLC, second overall with 34,998 total filings, demonstrated a distinctive pattern: filings climbed from 6,273 in 2021 to 8,114 in 2024.
- Banner & Witcoff, Ltd. (rank 14) and Greenberg Traurig (rank 22) both demonstrated resilience relative to peers, holding steady numbers — suggesting stable, possibly longer-term retainer-based client relationships.
International Case Exchange: The US as a Global IP Hub
The United States is the world’s largest recipient of international patent prosecution mandates. Inbound referral flows over 2021–2025 were dominated by Japan (141,193 cases), South Korea (89,016), and China (86,611) — a combined total that underscores the centrality of East Asian technology companies in driving US prosecution volume. Germany (23,611), Taiwan (13,775), and France (12,544) round out the top six source countries.
Outbound case flows tell an equally significant story. US applicants filed most heavily in China (185,866 cases), followed by Great Britain (108,618), Germany (85,945), Japan (79,402), and Canada (75,295). The breadth of this outbound activity — spanning over 40 destination countries — reflects the global ambitions of US-origin applicants and the international coordination demands placed on their prosecution firms.
Countries Sending Most Cases to US: Country Breakdown 2021-2025
Countries Receiving Most Cases from US: Country Breakdown 2021-2025
Strategic Insights for IP Law Firms
The data from 2021 to 2025 reveals a market in structural transition. Volume growth is no longer a reliable indicator of competitive strength in the US prosecution market. Firms that weathered the five-year recalibration most effectively tended to share several characteristics:
- High international exposure — firms with strong foreign client shares proved more resilient to domestic market fluctuations, as they benefit from global filing cycles that do not always track US-specific trends.
- PCT specialization — firms with PCT filing shares above 50% (such as Nixon & Vanderhye P.C. at 70%, Xsensus LLP at 69%, and Fish & Richardson at 62%) are better positioned to serve the cross-border strategies of multinational clients.
Final Thoughts
From 2021 to 2025, the US patent prosecution market remained the world's most active, even as filing volumes declined. The top tier is defined by high specialization, deep international connectivity, and the capacity to serve both domestic innovators and global applicants across complex, multi-jurisdictional portfolios.
Fish & Richardson's position at the top reflects not only scale but longevity. The high foreign-filing shares of firms like Sughrue Mion, Oliff PLC, and Birch, Stewart, Kolasch & Birch highlight how the US market functions as a global IP gateway — particularly for Japanese, Korean, and Chinese applicants seeking USPTO protection.
As patent strategies become more globally integrated and technologically specialized, US prosecution firms that invest in international alliances, digital workflows, and emerging technology expertise will be best placed to grow in the coming period. IP Pilot continues to track these dynamics in real time, providing firms with the competitive intelligence they need to identify partners, benchmark performance, and win mandates.
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