Parkinson will report to Pat Tomlinson, president and CEO of Mercer, and to Chris Lay, the current Marsh UK CEO. That reporting line will shift to Lisa Quest when she assumes the Marsh UK CEO role on 6 April.
In the position, Parkinson will oversee the strategic direction and commercial execution of Mercer UK's health and benefits, investments and retirement, and workforce and rewards businesses. He will also work with Marsh leaders to deliver the firm's capabilities across risk, strategy and people to UK clients.
He succeeds Benoit Hudon, who is leaving the business to pursue other opportunities. The two will work together during a transition period.
Parkinson inherits the role at a time of considerable upheaval in UK pensions and benefits consulting. The Pension Schemes Bill currently before parliament includes provisions for defined-contribution "megafund" consolidation, a new value-for-money framework, and a revamped defined-benefit surplus extraction regime.
All UK pension arrangements must also be connected to the pensions dashboard by October 2026.
Employer budgets are simultaneously under pressure. National insurance contributions rose from 13.8% to 15% in April 2025, following the Autumn 2024 Budget, while the payable threshold dropped from £9,100 to £5,000.
Mercer reported global revenue of US$6.2 billion for 2025, an 8% increase on the prior year, according to Marsh's Q4 earnings release. The firm manages approximately US$692 billion in assets globally and is widely regarded, alongside WTW, as one of the two largest benefits and HR consultancies worldwide.
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Mercer UK's footprint was reshaped in early 2024, when the firm sold its UK pension administration business. The operation Parkinson now leads is more tightly focused on advisory and investment work.
Parkinson joined Mercer in 2007 as an investment consultant in London. He was appointed UK wealth business leader in 2022 and has held a number of international leadership positions during his tenure.
Tomlinson said Parkinson's track record had positioned him to lead at a time of growing complexity. "His experience will be invaluable as we support our UK clients in navigating an increasingly complex economic environment and achieving successful outcomes for their stakeholders," he said.
Parkinson said he was focused on delivering results alongside the wider Mercer UK team. "I am very grateful for the trust and opportunity to lead Mercer's UK business. Together, with our team of exceptional colleagues, I am committed to creating the best outcomes for our clients," he said.
The appointment is the latest in a series of leadership changes at Marsh, following Quest's move into the UK CEO role upon Lay's retirement and the firm's rebrand from Marsh McLennan at the start of the year.
