Pedram Sameni
Nov 10, 2022

Patexia Insight 158: Top IPR Firms of 2022

PTAB Litigation

In early September, we published our sixth annual IPR Intelligence report. This popular report covers the IPR landscape by providing high-level statistics as well as evaluating and ranking all stakeholders participating in Inter Partes Reviews. We evaluated a five-year period, from July 1, 2017, through June 30, 2022. In the report, we have ranked IPR law firms, attorneys, petitioners, patent owners, and Administrative Patent Judges (APJ) under different categories (Petitioner, Patent Owner, and Overall) based on their activity and performance. In Patexia 150, we covered the outcomes of the IPRs. We further examined the terminated IPRs to find out how many were appealed before the Court of Appeal for the Federal Circuit (Patexia 154). Today’s insight will highlight some of the most active and best-performing IPR law firms involved in the 7,030 IPR challenges filed during the period of our study.

During this period, a total of 7,030 petitions were filed to challenge 4,966 unique patents and 77,846 unique claims. This has resulted in the institution and invalidation of 39,070 and 12,147 claims, respectively.

Our year-over-year analysis indicates that the IPR filings have fluctuated between 1,271 and 1,725. The activity peaked in 2017, then declined in 2018 at 6.84%, and reached the minimum in 2019 with 20.91% cases less than the previous year. In 2020, the activity increased again with 1,443 petitions, while in 2021, there was a decline of 9.70%. The data from the first half of 2022 shows a modest increase, with 669 petitions filed, 20 cases more than the 649 filed in the same period a year earlier.

During the period of our study, 2,471 companies have been active in one or more IPRs. There were 1,156 that acted as petitioners, and 1,541 as patent owners. Several companies acted as petitioners and patent owners in different cases. A total of 905 law firms have represented patent owners and petitioners in one or more of the 7,030 cases filed during the past five years. From this number, 446 firms represented petitioners, while 771 firms represented patent owners (some were active on both sides). In the following table, you will find a list of some of the very best IPR law firms mentioned either for their high activity or top performance (being named on this list means that the firm was in the top ten percent out of 905 firms):


Law Firm All Cases Patent Owner Cases Petitioner Cases Rank Category
Sterne, Kessler, Goldstein & Fox


249 233 2 PO Activity Rank
Perkins Coie 269 63 206 2 PO Performance Rank
Russ August & Kabat


233 5 3 PO Activity Rank
Merchant & Gould 41 21 20 3 Overall Performance Rank
Haynes and Boone, LLP


39 247 4 Petitioner Activity Rank
Lowenstein & Weatherwax 219 219 0 4 PO Activity Rank
Etheridge Law Group


212 0 5 Overall Performance Rank
Quinn Emanuel Urquhart & Sullivan 326 188 138 6 Overall Activity Rank
Gibson Dunn & Crutcher


11 50 6 Petitioner Performance Rank
Alston & Bird 199 69 130 11 PO Performance Rank
Erise IP P.A.


15 174 12 Petitioner Activity Rank
Norton Rose Fulbright 104 42 62 13 Petitioner Performance Rank
Wilson Sonsini Goodrich & Rosati


76 106 20 PO Activity Rank
Davidson Berquist Jackson & Gowdey 63 60 3 22 Overall Performance Rank
Sheppard Mullin


18 92 26 Petitioner Activity Rank
Greenberg Traurig LLP 112 27 85 28 Petitioner Activity Rank
Wolf, Greenfield & Sacks


52 79 29 Petitioner Activity Rank
Kilpatrick Townsend & Stockton 106 41 65 34 Petitioner Activity Rank
Klarquist Sparkman


18 58 38 Petitioner Activity Rank
Haug Partners 22 15 7 39 Overall Performance Rank
Mintz, Levin


57 21 40 PO Activity Rank
Fitch, Even, Tabin & Flannery LLP 48 48 0 48 PO Activity Rank


45 26 49 PO Activity Rank
Cravath Swaine & Moore 15 3 12 72 Petitioner Performance Rank
Choate, Hall & Stewart LLP


0 21 74 Petitioner Activity Rank
Allen & Overy 18 0 18 80 Petitioner Activity Rank
Katten Muchin Rosenman


3 14 93 Petitioner Activity Rank


  • Sterne, Kessler, Goldstein & Fox, with a total of 482 cases, was very active overall on both sides. Their activity was distinguished especially on the patent owner side representing them in 249 cases, which ranked them as the second most active firm for patent owners. They have worked closely with Xperi Corporation, Volkswagen Group of America, and Align Technology.
  • Perkins Coie was amongst the top ten active firms, but they earned their mention in this insight for their performance as they ranked second on the patent owner side, representing them in 63 cases out of 269 in total. Intel Corporation, Impinj, and Amazon were their top clients.
  • Russ August & Kabat focused mainly on the patent owners side, representing them in 233 out of 238 cases in total, and ranked 3rd as the most active firm on the patent owners side. They have worked closely with Realtime Adaptive Streaming LLC, Neodron Ltd., and Scramoge Technology Ltd.
  • Merchant & Gould stands out as one of the best performing firms, overall ranking third. They achieved this by representing the patent owners and petitioners in 21 and 20 cases, respectively. Cisco Systems, Huber Engineered Woods, and Otter Products are among their top clients.
  • Haynes and Boone, LLP representing petitioners in 247 out of 286 cases in total, ranked 4th as the most active firm on the petitioner's side. They worked closely with Apple Inc., Cisco Systems, and Unified Patents during the past five years.
  • Lowenstein & Weatherwax focused entirely on patent owners, representing them in 219 cases, and ranked 4th as the most active firm on the patent owner side. Seven Networks, Express Mobile, and VLSI Technology were their top clients. 
  • Etheridge Law Group was one of the most active firms representing patent owners in 212 cases. The firm was ranked the  5th best-performing firm overall. Uniloc, WSOU Investments LLC, and Ikorongo Technology were among their top clients.
  • Quinn Emanuel Urquhart & Sullivan ranked as the 6th most active law firm overall for representing patent owners and petitioners in 188 and 138 cases, respectively. They have worked closely with Samsung Electronics, Alacritech, and BlackBerry.
  • Gibson Dunn & Crutcher, with 50 cases on the petitioner’s side, was ranked the 6th best-performing firm on the petitioner’s side. Dell, Merck & Co, and Ericsson were their top clients over the past five years.
  • Alston & Bird ranked high on activity charts, representing petitioners and patent owners in 130 and 69 cases, respectively. The firm was ranked the 11th best-performing firm on the patent owner side. Nokia, Universal Electronics, and Dell Inc. were their top clients.
  • Erise IP P.A. represented petitioners in 174 out of 189 cases in total and was ranked the 12th most active firm on the petitioner side. This relatively small firm works closely with tech giants,including Apple and Sony Corporation.
  • Norton Rose Fulbright was active on both sides, representing patent owners and petitioners in 42 and 62 cases, respectively. The firm was ranked the 13th best-performing on the petitioner side. Qualcomm Technologies, Teladoc Health, and Booking Holdings Inc. were some of their top clients.
  • Wilson Sonsini Goodrich & Rosati represented petitioners and patent owners in 106 and 76 cases, respectively. They were ranked the 20th most active firm on the patent owner side. The firm works closely with Viatris, Align Technology, and Guardant Health.
  • Davidson Berquist Jackson & Gowdey was the 22nd best-performing firm overall. The firm represented both patent owners and petitioners in a total of 63 cases. Their top clients were Document Security Systems, Oyster Optics, and Blackbird Technologies.
  • Sheppard Mullin represented petitioners in 92 cases out of 110 in total and ranked the 26th most active firm on the petitioner side. Netflix, Snap Inc., and Hulu were their top clients during the period of our study.
  • Greenberg Traurig LLP was named for its activity on the petitioner side, representing them in 85 cases and ranking them as the 28th most active law firm. Satco Products, Universal Electronics, and Safco Products were their top clients.
  • Wolf, Greenfield & Sacks was active on both sides with a total of 131 cases. The firm was the 29th most active firm regarding the petitioner side. Their top clients were Google, Husky Injection Molding Systems, and IP Bridge
  • Kilpatrick Townsend & Stockton was active on both sides, representing patent owners and petitioners in 41 and 65 cases, respectively. The firm was ranked as the=34th most active on the petitioner side. They have closely worked with Gree Inc., Laboratory Corporation of America Holdings, and Axonics.
  • Klarquist Sparkman ranked the 38th most active firm on the petitioner side, representing them in 58 out of 76 cases in total. Microsoft Corporation, SAP AG, and Motorola Solutions were their top clients during the period of our study.
  • Haug Partners was ranked the 39th best performing firm overall. Their top clients were Nektar Therapeutics, NEXRF CORP, and Bentley Motors Limited.
  • Mintz, Levin represented patent owners in 57 out of 78 cases in total. The firm was ranked as the 40th most active firm on the patent owner side. Koninklijke Philips, Avigilon, and Eyenovia, Inc. were their top clients.
  • Fitch, Even, Tabin & Flannery LLP represented patent owners in 48 cases and was ranked as the 48th most active firm on the patent owner side. The firm’s top 3 IPR clients were Lone Star Silicon Innovations LLC, Ancora Technologies, and Quartz Auto Technologies.
  • Polsinelli represented patent owners on 45 out of 71 cases in total. This placed them as the  49th most active firm on the patent owner side. Halliburton Company, Power2B, and Anza Technology Inc. were their top IPR clients.
  • Cravath Swaine & Moore ranked the 72nd best-performing firm for representing petitioners. Their top IPR clients include Abiomed, ADT Security Services, and Blue Yonder Group.
  • Choate, Hall & Stewart LLP represented the petitioners in a total of 21 cases and ranked as the 74th most active firm. Foundation Medicine, Regeneron Pharmaceuticals, and Resideo Technologies were their top IPR clients.
  • Allen & Overy, with a recent expansion in IP, represented petitioners in a total of 18 cases and ranked as the 80th most active law firm. They have closely worked with Fresenius Medical Care, ResMed, and Meta Platforms, Inc.
  • Katten Muchin Rosenman represented petitioners in 14 out of 17 cases in total and ranked the 93rd most active firm on the petitioner side. Direct Packet Research, Sawai Pharmaceutical Co., and Viatris were their top IPR clients.



The full IPR Intelligence Report includes high-level statistics about the petitions, IPC codes, IPR outcomes, its analysis, and the work and performance of PTAB judges. Similar to last year, we have provided a list of the lateral moves that took place since our previous report.


We have updated and improved our ranking methodology every year since the release of our first report in 2017, using feedback from our community through direct communication or by conducting surveys. This feedback and the experience we have gained over time have helped us improve and make the rankings more relevant and useful.

For the Activity Score, we understand that the company’s in-house counsel would prefer to hire somebody with more activity and experience in recent years over somebody active five years ago. Accordingly, our activity score formula gives more weight to more recent cases compared to older cases. As a result, an entity involved in a total of 50 cases filed in 2017 ranks slightly lower than another entity with the same 50 cases but distributed over the five-year period.

Furthermore, we calculated the activity score as a logarithmic function to avoid large gaps between entities with more cases than the average. . This makes the comparison between entities with different activity levels easier.

As for the Success Score, we only considered terminated cases. One of the updates for this year’s ranking methodology is the new scoring assigned to FWD Entered outcomes. In cases where not all claims are invalidated, we understand that if the surviving claims were part of a district court case, that is good news for the patent owner (or plaintiff in the district court case), because they can still move forward and potentially claim damages for infringed claims in the district court. Therefore, from that perspective, it would be considered a victory for the patent owner. However, when it comes to IPR, the attorneys representing the petitioner have also damaged the patent by invalidating possibly some of the asserted claims. They could  leverage this  by negotiating more favorable terms in a settlement. Therefore, they deserve recognition for their work and get at least 0.5 points for one invalidated claim. If they manage to invalidate more than one claim, then they get more credit for the outcome, as summarized in the table below:


Status PO Success Points Petitioner Success Points

1 Point

0 Point
Terminated-Settled 0.25 Point 0.75 Point
FWD Entered
(no claims invalidated)
1 Point 0 Point
FWD Entered
(at least one claim invalidated)
1 - Petitioner Success Point 0.5 + 0.5 x Claims Invalidated/Claims Listed
Terminated-Adverse Judgement 1 Point 0 Point


To calculate the Performance Score, we combined the Activity and Success Scores. This was done as large case numbers will inevitably dilute the performance over time. It makes it unideal to compare the performance scores of firms/attorneys with different caseloads, even after excluding firms with low activity. The Performance Score, which allows us to score and rank companies, attorneys, and firms for both Activity and Success combined, is a weighted average of success and activity scores. It helps companies find highly active and  successful law firms and attorneys for their cases.

Stay tuned for more insights related to the IPR Intelligence Report, as in the following weeks,we will cover some of the best IPR attorneys as well as some of the best CAFC attorneys and law firms in 2022 with data from our latest CAFC Intelligence 2022.