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Gavin Costelloe is a member of Greenberg Traurig’s White Collar Defense & Investigations Practice in London and represents clients in high-stakes criminal and regulatory matters. Gavin is a former senior prosecutor for the UK’s Serious Fraud Office (SFO) and advises companies and individuals across multiple industries on complex, cross jurisdictional internal, government and regulatory investigations. He advises companies on the UK’s failure to prevent offences relating to bribery and corruption, fraud and tax evasion, as well as compliance with and the risk management of legislation and regulations concerning these offences, money laundering, financial and trade sanctions, and sustainability, human rights and supply chain risk and other matters that fall within the scope of ESG risks.

Gavin handles cases involving domestic and overseas law enforcement including the SFO, the Crown Prosecution Service (CPS), the Office of Financial Sanctions Implementation (OFSI), Companies House (CH), the Competition and Markets Authority (CMA), and he is experienced liaising with overseas law enforcement including the U.S. Department of Justice (DOJ), the Commodity Futures Trading Commission (CFTC) and the Securities & Exchange Commission (SEC). Gavin also provides advice to and defends senior executives and compliance professionals, subject to a range of criminal and regulatory offences and violations.

Capabilities

Experience

  • Advised individual and corporate clients on the impact of and compliance with the UK’s financial and export control sanctions regimes with respect to a range of activities, transactions and exports, and drafted voluntary self-reports to the UK’s Office of Financial Sanctions Implementation.
  • Acted for a number of global corporations, including a number of electronic money institutions and international construction businesses, in connection with a range of corporate governance, compliance and other corporate crime risks matters, including bribery & corruption, anti-money laundering and UK financial and export control sanctions matters.
  • Acted for a former partner of an international law firm prosecuted for offences of fraud and money laundering in relation to a financial investment scheme involving a £10 million fund. Following submissions at the close of the prosecution case, the judge ruled the case was not safe and our client was acquitted of all charges.
  • Acted for a number of corporations and individual directors in relation to prosecutions and threats of prosecution by Companies House in connection with violations of director duties, including the late filing of accounts.
  • Acted for a UK based financial services firm in respect of an internal investigation into alleged regulatory breaches.°
  • Acted for a UK manufacturing company in respect of an internal investigation into alleged breaches of EU and U.S. financial sanctions.°
  • Represented a global extractives company in respect of internal and governmental investigations into alleged bribery and corruption conducted by the SFO, DOJ, SEC, and the Australian Securities and Investments Commission.°
  • Advised the former CEO of a multi-national company subject to investigation by the SFO, DOJ, and SEC concerning allegations of bribery and corruption.°
  • Represented the former CEO of a company in a HMRC and CPS prosecution concerning multiple counts of conspiracy to cheat the public revenue and money laundering.°
  • Represented one of six defendants on charges of conspiracy to defraud brought by the SFO concerning manipulation of the LIBOR benchmark.°
  • Advised an individual subject to SFO investigation into multi-jurisdictional bribery and corruption allegations.°
  • Represented an individual subject to HMRC prosecution involving multiple counts of cheating the public revenue.°
  • Represented the former director of a manufacturing company subject to investigation by the CMA for suspected market manipulation and price fixing allegations.°

°The above representations were handled by Mr. Costelloe prior to his joining Greenberg Traurig, LLP.

  • UK Serious Fraud Office, 2019-2022
    • Case Controller
    • Principal Investigative Lawyer
  • Legal Caseworker, Crown Prosecution Service, 2007-2008

Recognition & Leadership

  • Listed, Best Lawyers in the United Kingdom, "One to Watch," Criminal Practice and Litigation, 2025
  • Listed,The Legal 500 United Kingdom, 2024
    • Regulatory Investigations and Corporate Crime, 2024
    • White-Collar Crime, 2024
  • Member, The Law Society of England & Wales

Credentials

Education
  • LL.M., BPP Law School
  • Bar Vocational Course, BPP Law School
  • GDL, BPP Law School
  • Bachelor’s Degree, King's College London
Admissions
  • England and Wales