'excellent at dealing with complex legal and policy issues.’
Legal 500 2021


Tom Ataii is a senior associate in the Litigation & Dispute Resolution practice of the London office. He joined Mayer Brown in 2013 having previously worked for another international law firm.

Tom has broad commercial dispute resolution experience, with a focus on claims against professionals and banking and finance litigation. He has taken high-profile cases to successful determinations in the High Court, the Court of Appeal and the Supreme Court.

Spoken Languages

  • English


  • Acting for the business valuation arm of an international bank in connection with allegations of negligent overvaluation of a business and related intellectual property.
  • Acting for AIG in respect of its claim for a declaration that a large number of claims asserted against a law firm, for whom AIG provided qualifying insurance, fell to be aggregated and thus considered a single claim under the relevant insurance policy. The first consideration by a court of the aggregation wording in the SRA Minimum Terms and Conditions of Professional Indemnity Insurance. Successful appeals to the Court of Appeal and the Supreme Court. AIG Europe Ltd v OC320301 LLP [2015] EWHC 2398 (Comm); [2016] EWCA Civ 367; [2017] UKSC 18.
  • Advising a management company in connection with claims by an international investment bank and others for declarations of non-liability, in connection with loan notes and related financial instruments.
  • Successfully defending the solicitor Defendant, Collyer-Bristow, against a claim by 550 investors in tax-advantaged technology investment schemes, after a 16 week trial. Andrew Brown and others v Innovatorone Plc and others [2012] EWHC 1321 (Comm).


Nottingham Law School, LPC

Warwick University , BA


  • England and Wales
  • Listed as a 'key lawyer' for Insurance and Reinsurance. ‘I work with Will Glassey and Tom Ataii – both excellent at dealing with complex legal and policy issues.’ (Legal 500 2021).