Samir Deger-Sen

Samir Deger-Sen is an experienced appellate lawyer, who represents clients in their most complex litigation matters.

Mr. Deger-Sen focuses his practice on Supreme Court and appellate litigation and is widely recognized as one of the leading appellate lawyers of his generation. He has argued over 15 times in appellate courts across the country, including the US Supreme Court, and has successfully represented clients in the technology, media, and financial sectors in their highest-stakes appeals. In the last year alone, he was named three times in The American Lawyer’s Litigator of the Week feature for his successful arguments on behalf of Meta Platforms, the Hollywood Foreign Press Association, and Brigade Capital Management. He has been recognized by Law360, Bloomberg Law, and Lawdragon as one of the top appellate attorneys nationwide under the age of 40.

Mr. Deger-Sen has been a primary author of more than one hundred briefs involving a wide range of constitutional, statutory, and administrative law issues. In the Supreme Court, he has been a lead brief writer in multiple merits cases, has successfully persuaded the Court to grant certiorari on several occasions, and has been lead counsel to national organizations filing amicus briefs before the Court. He also has significant trial-level experience, including first chairing depositions, drafting and arguing dispositive motions, and authoring critical briefs in numerous international arbitrations. Mr. Deger-Sen is resident in both the firm’s New York and London offices and is available to help UK-based clients navigate novel, complex, and challenging questions of US law.

Mr. Deger-Sen has particular experience in class actions and is proficient in substantive Rule 23 law. He has been the primary author of briefs involving some of the largest putative classes in the country, including defending clients against multi-billion dollar class actions in the Second and Ninth Circuits. Notably, Mr. Deger-Sen has, on multiple occasions, successfully secured interlocutory appellate review of class certification decisions, which is granted in only a small fraction of cases. He also regularly advises on complex class action issues in district court litigation.

In addition, Mr. Deger-Sen has significant experience in securities appeals. Over the past two years, he has successfully obtained complete dismissal of claims in several securities class actions on appeal in the Second and Ninth Circuits.

Mr. Deger-Sen has an extensive pro bono practice, where he has acted as lead counsel in high-profile constitutional litigation, including multiple precedent-setting victories in the Ninth Circuit.

Before entering private practice, Mr. Deger-Sen was a law clerk at all three levels of the federal judiciary. He clerked for Justice Anthony Kennedy of the US Supreme Court, on the Ninth Circuit Court of Appeals, and on the District Court for the District of Hawaii. Before law school, Mr. Deger-Sen was a lecturer in International Politics at Oxford University, where he taught several undergraduate level courses.

Mr. Deger-Sen has substantial public speaking experience. He is the winner of numerous national debating competitions and a former World University Debating Champion.