Mr Simmonds announced he was leaving Bluefin at the beginning of January to pursue other interests after working for the firm since August 2007.
He worked as chief executive until March 2011 then as chairman until his departure.
When asked if a replacement had been appointed yet, a spokesman for Bluefin said: “There’s no need for that role anymore. It’s not necessary to have a chairman when the company is part of AXA anyway.”
He indicated the chairman position had been created for Mr Simmonds after his position as chief executive was replaced by Nick Burns.
Mr Simmonds is not the only big name to leave the firm recently.
Head of research and development David Cartwright announced he was leaving the firm this week to join Defaqto.
He had worked for Bluefin for eight years and will be working for the financial research group as a head of insight responsible for research activity and third party and provider relationships.
Bluefin Advisory Services was put up for sale by owners AXA in November and could fetch £100m.