Long-serving Aegon UK chief executive (CEO) Adrian Grace will be replaced by Mike Holliday-Williams on 1 October.
Grace's replacement has joined from Direct Line, where he was managing director of personal lines.
Grace became CEO of what was broadly a pensions company back in 2011 and has overseen its transformation into an investment platform and pensions business. Aegon said he would step down to retire.
While Grace (pictured) oversaw growth and transformation in the business, his last few years at the top also saw the company struggle to get hold of its re-platforming of Cofunds.
Aegon completed the re-platforming of the former Legal & General platform, which it bought for £140m back in the summer of 2016, on 8 May last year. The move saw £37bn of advised assets and 400,000 clients move to new technology over the course of a single weekend and PP sister title, Professional Adviser, has since revealed the struggles Cofunds users and advisers suffered, which took months of fixing.
The trouble caused led to Aegon writing an apology just five weeks after the migration saying it was sorry for allowing service levels to fall "below the standards" expected of it.
Clients and advisers were not able to execute transactions, for example, while many did not receive their monthly income payments and some advisers also reported extensive delays with the platform's contact centre.
Aegon global CEO Alex Wynaendts said: "Mike's appointment signals Aegon's continuing commitment to build on the strong foundation of our UK business. Mike brings extensive experience in the financial industry and a strong track record in focusing on customer solutions.
"We would like to thank Adrian for having successfully modernised, transformed and repositioned our UK business. Under his leadership, our UK business has grown from £40 billion of unit-linked pensions in 2009, to today where we oversee £175 billion of pension and investment assets."
He added: "We have repositioned Aegon to be the leader in the market of investment trading platforms and the company is now well positioned for further growth. We wish Adrian well in his deserved retirement."
The changes come as the firm's master trust was today confirmed as approved by The Pensions Regulator, joining 26 other authorised schemes.
Pension Protection Fund (PPF) chief financial officer Andy McKinnon is stepping down from his role after seven years.
Aon has announced the promotion of seven of its UK retirement, asset management and reward team to partner.
Amber Rudd has resigned as secretary of state for work and pensions with immediate effect, with Thérèse Coffey named as her successor.
Muse Advisory has refreshed its management structure with four senior promotions.