Stuart O’Brien



Stuart has experience of a broad range of pension related matters, advising employers and trustees alike with a particular emphasis on finance and investment issues.  This includes buy-ins and buy-outs, de-risking and advising on the legal aspects of scheme funding issues, including the use of contingent assets.

Stuart’s advice includes making changes to pension benefits (including the closure of schemes to future accrual), liability management exercises including pension increase exchange and pre-retirement transfer exercises, as well as scheme mergers, demergers, and solvent and insolvent wind-ups. He also has significant expertise advising on the pensions aspects of corporate mergers, acquisitions and restructuring, dealing with Pensions Regulator clearance, section 75 debts, and apportionment and withdrawal arrangements.

Stuart is also a leading industry figure for environmental, social and governance (ESG) investment issues and is an authority and regular speaker and commentator on the integration of climate change into trustee investment decision making as well as TCFD reporting, stewardship and engagement issues.

He chairs the Pensions Climate Risk Industry Group and sits on a number of high profile committees including recent PLSA working groups providing trustee guidance on ESG and implementation statements. Stuart is a member of the Investment and Defined Contribution Sub-Committee of the Association of Pension Lawyers and a member of the legal panel to the Impact Investment Institute.

Recent experience

  • Assisting clients with the settlement of deferred and pensioner liabilities via buy-in and buy-out bulk annuity transactions. Having assisted the trustees of the Friends Provident Pension Scheme on their ground breaking collateralised buy-in of pensioner liabilities with Aviva in 2008, Stuart has advised on numerous other transactions with all major insurers over the last decade including residual risk policies and umbrella agreements.
  • Advising Trustees on ESG matters in investment strategy and decision making, including consideration of fiduciary duties.
  • Helping trustees create comprehensive responsible investment policies and reporting, including frameworks for engagement, exclusions and climate-risk reporting in line with the recommendations of the TCFD.
  • Advising Trustees on DC investment issues, including the use of platform structures, asset security, changes to member funds and transition to DC master trusts.
  • Advising on the merger and sectionalisation of pension schemes including complex structures involving flexible apportionment arrangements.

Memberships and Qualifications

Membership of professional bodies:
Association of Pension Lawyers
(Full Member and Investment Committee Member)
Pensions Management Institute (Ordinary Member)

Career history

Qualified: 2003, England & Wales

Pensions experience since: 2003

Joined Sackers: 2003, Associate: 2008

Joined partnership/LLP: 2011

Employers: Hammonds (2001-2003)

Academic history


Nottingham Law School (2000-2001)
University of Texas Law School, Austin, USA (1998-1999)
University of Nottingham (1996-2000)

Degree: LLB (with merit in American Law), Nottingham University
Legal Practice Course

Further Information


  • “Main contact point was through Stuart O’Brien who was always able to provide a clear, concise explanation of technical pension subject matters to non-technical individuals.” – Legal 500 2023
  • “Stuart led our pioneering analysis of the compatibility of pension trustee fiduciary duties and impact investing with characteristic thoroughness and creativity, while maintaining a focus on the end product.”
    Bella Landymore, Policy director, Impact Investing Institute
  • He is “pragmatic and does not waffle”. Legal 500 2014 recommended lawyer