Guillaume Buell



Guillaume Buell focuses on prosecuting complex securities fraud cases on behalf of institutional investors, and advises leading pension funds and other institutional investors in the United States and Canada on issues related to corporate fraud in the U.S. securities markets. He also advises foundations and endowment funds on monitoring the well-being of their investments.

Currently, he is prosecuting securities class actions against Nu Skin Enterprises, Biogen, Genworth Financial, Innerworkings, and Castlight Health. Guillaume was part of the team that secured a $48 million recovery in the securities fraud action against the nation’s largest pharmacy retail chain, CVS Caremark. He also played an integral role in the $9 million recovery secured for investors against Vocera Communications, the leading provider of mobile communication solutions.

Prior to joining Labaton Sucharow, Guillaume was a litigation associate at Cahill Gordon & Reindel LLP, where he represented major corporations and their officers and directors in the financial, consumer, pharmaceutical, and insurance sectors in commercial and securities litigations and consumer class actions in state and federal courts, state and federal government investigations, and internal investigations.

Guillaume received his J.D. from Boston College Law School, and was the recipient of the 2009 Boston College Law School Award for outstanding contributions to the law school community. Guillaume was also a member of the National Environmental Law Moot Court Team, which advanced to the national quarterfinals and received best oralists recognition. While in law school, Guillaume was a judicial intern with the Honorable Loretta A. Preska, United States District Court for the Southern District of New York, and spent his third year of law school as an intern with the Government Bureau of the Attorney General of Massachusetts. He received his B.A., cum laude with departmental honors, from Brandeis University. While at Brandeis, Guillaume was also a Research Associate with the Pioneer Institute for Public Policy Research in Boston.

Guillaume is an Eagle Scout and a member of the Board of Directors for the Manhattan Council of the Boy Scouts of America. He is fluent in French.


Boston College Law School
J.D., 2009

Brandeis University
B.A., cum laude with departmental honors, 2006


2009, Massachusetts
2010, New York

2014, U.S. Supreme Court

U.S. Court of Appeals
2016, First Circuit
2014, Second Circuit

U.S. District Court
2010, Southern District of New York
2010, Eastern District of New York
2012, Southern District of Texas
2012, Eastern District of Texas
2013, Northern District of Texas