Brian O'Sullivan
Partner – US Irish Business Group

Brian O'Sullivan


Brian is a Partner of our Financial Services division, bringing his depth of experience to engagements across both our audit and advisory departments. Brian originally started with the firm in 2007 before spending over three years with one of Ireland’s pillar banks, a further three within the banking and capital markets team of a big 4 firm and returning back to Grant Thornton to assist with the growth of our financial services offering.

Brian will be based out of New York (post COVID) to lead our US/Ireland desk and the collaboration of our offerings between Grant Thornton US and Grant Thornton Ireland.

Experience – Audit

Brian brings a depth of audit experience, specializing in the asset management, banking and fintech sectors. His portfolio of audit clients has included:

  • Cross European banking group listed on the London Stock Exchange
  • Local and captive credit institutions, including one of Ireland’s three largest retail banks
  • Special Purpose Vehicle groups
  • Hedge Fund and Private Equity clients
  • Established and start-up fintech groups
  • Crypto currency companies
  • ISA and PCAOB experience

Experience - Advisory

At an individual level Brian specializes in advising on the implementation of new accounting standards, design and operational risk assessments, governance reviews, resource enhancement and providing practical solutions to complex problems. He has a wide range of experience in Asset Management and Banking, both domestically and internationally. In recent years his experience includes:

  • SOX review and reporting engagements
  • System and Organizational Controls reporting
  • Control framework assessments - both design and operational effectiveness review
  • Implementation projects and impact assessments for the implementation of IFRS 9 Expected Credit Loss models, IFRS 15 Revenue and IFRS 16 Leasing
  • Outsourced financial reporting projects for some of the largest global asset management administrators
  • Resource augmentation
  • Re-design of CFO/CEO/CRO board reporting packs
  • Lease portfolio review for global asset portfolio; forensic review of issues and resulting re-design of operational control framework
  • Non-performing asset - strategy assessments
  • Collateral valuation project in advance of portfolio disposal
  • Leading large scale project management assignments for Fund Administrators
  • Development of basic repayment capacity cash-flow models for a pillar bank
  • Member of Chartered Accountants Ireland (CAI)
Brian O'Sullivan
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Partner – US Irish Business Group
Brian O'Sullivan
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