Mencap's head office is on London's Old Street
The Royal Mencap Society has completed a £61m bulk annuity transaction for its pension plan covering benefits for 710 members.
The deal is the first for the UK charity and was completed with Canada Life using an internal legal process of the insurer's that is conducted in conjunction with Aon.
The Mencap Pension Plan was advised by Aon for the deal, which is the first for the charity's pension scheme.
Chair of trustees Sally Pococke said the bulk annuity transaction was "a significant achievement" in the scheme's strategy to continually reduce risk in the Mencap Pension Plan and improve members' security.
"The trustees appreciated the guidance and expertise provided by the Aon team which enabled us to have open and constructive dialogue with Royal Mencap Society as we moved through the process."
Aon senior consultant Joe Hathaway said: "Aon's Pathway process and use of pre-negotiated contracts, together with nimble trustee decision-making, were fundamental in allowing the plan to move quickly and to complete the transaction once Canada Life was selected as the preferred insurer.!
The Mencap Pension Plan also received transaction legal advice for the deal from Eversheds Sutherland.
Pathway - the Eversheds Sutherland and Aon bulk annuity service set up in 2014 - has now been used to complete in excess of £1bn of deals.
