Terms of the transaction, which is expected to close late this year subject to regulatory approvals, were not revealed.

Founded in 2000, Cardano is a long-term savings specialist in the UK and the Netherlands, with approximately $66bn (£52bn) in assets under management.

Cardano offers a range of fiduciary management, investment advisory services, and liability-driven investing and derivatives solutions to both DB and DC pension schemes in the UK and the Netherlands, the two largest pensions markets in Europe.

Cardano acquired workplace pension provider Now Pensions five years ago, which means it operates the third largest UK master trust platform, serving more than two million savers across 27,000 employers. 

Michael Dempsey, Mercer’s wealth president, said: “The acquisition and alignment of our expertise and capabilities represents a unique and timely combination to support pension clients and other institutional investors and their evolving needs.”

Benoit Hudon, Mercer’s UK president and chief executive, said: “Our combined talent and capabilities will position Mercer as the pension provider of choice in the UK and the Netherlands. This will allow us to continue to expand globally beyond pensions to serve other large asset owners, including endowments and foundations, family offices and insurers.”

Michaël De Lathauwer, Cardano Group’s chief executive, said: “We share an aligned culture with Mercer and together, we are committed to being the best solutions provider for UK and Dutch pension schemes. We look forward to being one multi-disciplinary team and helping our clients navigate the evolving pension and investment landscape.”

As part of the agreement, approximately 550 Cardano colleagues in London, Nottingham and Rotterdam will join Mercer, upon completion of the transaction.

Mercer is owned by Marsh McLennan, a professional services firm in the areas of risk, strategy and people, which has more than 85,000 workers and annual revenue of $23bn (£18bn).