Constantine Cannon LLP
address 1 Paternoster Square

We are one law firm with two internationally renowned practices – antitrust and representing whistleblowers. We also excel at litigation, compliance, intellectual property, and art law.

We’re a different kind of firm. We listen. We analyze. We apply extensive legal knowledge and decades of experience. We fight for our clients from beginning to end. We know that lawyering is more than arguing and that litigation entails more than fighting. Constantine Cannon attorneys negotiate, collaborate, and persuade.

Our experience in antitrust and unfair practice litigation is unmatched, and we’ve won some of the largest antitrust judgments in history. Our whistleblower attorneys help our clients expose wrongdoing and brought those clients $240 million in whistleblower rewards.

We also serve clients in commercial litigation, intellectual property, and art and cultural property law, as well as in government relations and corporate compliance, monitoring, and investigations. We have extensive experience in electronic discovery, and provide e-discovery consulting.

Founded in 1994 in New York City, Constantine Cannon has more than 65 attorneys working coast to coast – in New York, Washington, D.C., San Francisco – and in London, where our global practice supports clients throughout Europe, the Middle East, Africa, and the Far East, across more than a dozen languages.