UK - Mark Hyde Harrison, chief executive at the £19bn (€22bn) Barclays UK Retirement Fund, has left the pension plan early this week, IPE understands.
No reasons have been given for his departure.
Hyde Harrison became chief executive at the pension fund in 2006 after he served as its chief investment officer.
He joined Barclays in 1988, having worked in the US and Canada and served as UK sales director at Barclays Life, Pension and Investment products.
Hyde Harrison said: "It has been a pleasure to be involved with the Barclays UK Retirement Fund for the last ten years, and leading it for the last five. I have enjoyed my time there and wish it every success in the future."
In June this year, Hyde Harrison was named chairman of the UK's National Association of Pension Funds (NAPF), succeeding Lindsay Tomlinson.
He has been a member of the NAPF Investment Council since 2006 and previously served as vice-chairman of the association.