John Costello

John CostelloFCA - Manager

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John was born and educated in the Republic of Ireland. After graduating from Dublin City University, he trained to become a chartered accountant and qualified, becoming a member of Chartered Accountants Ireland, in February 1991.

John moved to the Isle of Man in May 1991 to work with BDO Binder in auditing. He then joined one of the ‘Big 4’ firms from 1999 until 2018.

During his career John has worked in auditing, accounts preparation and latterly on business advisory and insolvency assignments. He has extensive experience in Isle of Man Voluntary and Court Appointed liquidations and receiverships, including dealing with multi-jurisdictional/cross border aspects and with fraud and investigation cases, plus complex asset recoveries and disposals.

John joined CM in September 2018, with responsibilities covering the preparation of financial statements for companies and trusts, company and personal taxation returns, administration of companies and trusts plus dealing with voluntary liquidations.

John is a keen golfer and enjoys playing on one of the Island’s many courses. He is also a competitive chess player and an active member of the Isle of Man Chess Association playing locally and in the UK and Ireland.

Latest News

  • 🏌️Mike Vipond – 50 Years as a Professional🏌️

    CM Partners was proud to sponsor the Mike Vipond – 50 Years as a Professional event last weekend, celebrating an incredible milestone in Mike’s golfing career.   Congratulations to the worthy winners of the 50 Years a Pro Competition, who achieved an astonishing 92 points:   🏆 Michael Allison 🏆 Nicola Diane Vincent 🏆 Thomas

    8 July 2026
  • 🍝🍕 Pizza Pasta 🍕🍝

    Great to see our CM Partners team coming together this week over a series of team lunches.   From Directors to Trainees, it’s been a fantastic opportunity to connect across levels, share experiences, and strengthen working relationships.   Building a collaborative culture is at the heart of what we do, and these moments make all

    21 May 2026
  • Celebrating 20 Years of Growth, Leadership and Commitment at CM 🌟

    At CM Partners, we believe that great businesses are built by great people — and this year, we are proud to celebrate an incredible milestone for four of our directors.   In 2026, Hazel, Blair, Tom, and Sam each mark 20 years with the firm, having started their journeys with us as trainees and grown

    19 May 2026

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