Casey Determan
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Casey Determan

Associate

Casey’s broad-based practice focuses on securities litigation, internal and government investigations, and regulatory compliance. 

He has represented financial institutions and other major companies in connection with high-stakes class actions and other complex civil litigations.  Casey has advised corporate clients in connection with investigations concerning financial services, anti-corruption, national security, and sanctions.  He also contributes to the firm’s publications regarding M&A litigation and corporate governance, sanctions, and the Foreign Corrupt Practices Act (FCPA).

Prior to law school, Casey advised government clients on policy and strategy.  He has helped private sector clients navigate the evolving security landscape and expand into federal markets.  Casey also served as a junior legislative aide focused on homeland security issues.

Expertise

Industries

Experience

Representative matters

  • Advised Middle East-based company on sanctions-related due diligence in relation to a transaction involving a Russian entity.
  • Advised Asia-based fund on U.S. sanctions and trade restrictions related to Russia's energy sector.
  • Advised Asia-based multinational company on U.S. sanctions and export control compliance.
  • Represented Canadian financial institution in SEC and CFTC investigation.
  • Represented U.S. company in securities class action.
  • Represented U.S. financial institution in antitrust litigation.
  • Represented corporate officer in shareholder derivative litigation.

Qualifications

Admissions

Attorney-at-Law, State of New York, 2023

Attorney-at-Law, District of Columbia, 2025

Academic

BS/BA, cum laude, Economics and Political Science, Southeast Missouri State University, 2012

MA, Defense & Strategic Studies, Missouri State University, 2014

JD, magna cum laude, William & Mary Law School, 2022

Disclaimer
A&O Shearman was formed on May 1, 2024 by the combination of Shearman & Sterling LLP and Allen & Overy LLP and their respective affiliates (the legacy firms). Any matters referred to above may include matters undertaken by one or more of the legacy firms rather than A&O Shearman.