Perpetual pension development director Fiach Maguire has left the company following its £1.05bn deal to merge with Invesco last October.
Maguire's departure follows the decision to merge Perpetual's pension operation with Invesco's.
Maguire, 42, has been regarded as one of the most influential voices calling for a greater role for fund managers in pension provision and was previously the head of Autif's pension committee.
He joined Perpetual in January 1997 and is planning to take a career break while considering a number of projects.
He says: “We agreed there was no longer a suitable senior role for me but I have had four very enjoyable years at Perpetual and I wish all my pension colleagues the best.”
Perpetual was unavailable for comment.