Constantine Cannon LLP
Rankings
Leading firm in USA 2026
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Overview
Provided by Constantine Cannon LLP
Constantine Cannon, with offices in New York, Washington, D.C., and San Francisco, is an internationally known law firm focused on antitrust and whistleblower representation. Its antitrust practice has secured three of the top five antitrust recoveries ever. The firm’s whistleblower practice has likewise secured record recoveries for the government and the firm’s clients amounting to more than $1.5 billion in total.
Work & experience
Provided by Constantine Cannon LLP
Constantine Cannon’s antitrust practice has extensive experience representing clients nationwide, from Fortune 100 businesses (including 4 of the top 10) to start-ups and individuals, and across all areas of antitrust and competition law and all industry sectors. The firm’s whistleblower practice has extensive experience representing whistleblowers under the wide array of whistleblower rewards statutes and programs. Our approach is to always be prepared to go to trial if necessary.
Notable work
Provided by Constantine Cannon LLP
In Re Payment Card Interchange Fee and Merchant Discount Litigation
Represented 60+ merchants challenging Visa/Mastercard interchange fees and anticompetitive network rules.
Sidibe et al. v. Sutter Health
Healthcare antitrust class action against Sutter Health; Ninth Circuit reversed defense judgment in 2024.
Multiple Record False Claims Act Recoveries, 2020-2026
Constantine Cannon successfully represented the whistleblowers in multiple False Claims Act cases.
Ranked Offices
Provided by Constantine Cannon LLP
USA - Head office
New York
22 Vanderbilt Avenue 15th Floor , New York, New York, USA, 10017, New York
Ranked Departments
Ranked Individuals
Constantine Cannon LLP
Top figures
34
Lawyers
3
Offices
1994
Established in
Key people
Industry sectors
Capabilities
Clients
Content provided by Constantine Cannon LLP