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Gavin Costelloe is a senior associate in Greenberg Traurig’s White Collar Defense & Special Investigations Practice in London. Gavin is a former lawyer and prosecutor for the UK’s Serious Fraud Office (SFO). Gavin advises companies and individuals on internal, government and regulatory investigations and compliance issues related to the UK Bribery Act, fraud, market manipulation, anti-money laundering, economic sanctions, and other serious and complex cross-jurisdictional matters. Gavin has considerable experience assisting with diligence for mergers, acquisitions, and other investments including in jurisdictions with high corruption risk.

Gavin’s practice is focused on business crime investigation, defence, compliance, and risk mitigation. This includes assisting companies with internal, government, and regulatory investigations (including those conducted by the SFO, Her Majesty’s Revenue & Customs (HMRC), the Crown Prosecution Service (CPS) and the Competition and Markets Authority (CMA)), individual defence for senior executives and compliance professionals, and devising and implementing internal training and compliance programmes.

Gavin is experienced in liaising with overseas law enforcement including the U.S. Department of Justice (DOJ), the Commodity Futures Trading Commission (CFTC), the Securities & Exchange Commission (SEC), and the Swiss Office of the Attorney General (OAG), as well domestic UK law enforcement, in relation to parallel investigations.



  • 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, The Legal 500 United Kingdom, 2024
    • Regulatory Investigations and Corporate Crime, 2024
    • White-Collar Crime, 2024
  • Member, The Law Society of England & Wales


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