Peter Gallagher, the head of agency at Erinaceous in Manchester who has resigned, has declined to confirm speculation he is setting up his own practice.
Gallagher resigned at the same time as Paul Day, head of industrial, and Phil Meakin, head of office agency in Manchester.
All three are currently negotiating the length of notice they must serve and have declined to comment on future plans until discussions are finalised.
Gallagher said: "Our absolute focus has to be looking after clients."
Gallagher added he was excited about the future and would be staying in Manchester. He has worked for Erinaceous, in its many forms, for 35 years.
Erinaceous was formerly known as Dunlop Heywood before changing its name to Dunlop Haywards. In 2005, several high-profile advisers including Gallagher's office agency colleague Tony Bray left to set up Cushman & Wakefield in Manchester. Later, Bob Dyson, the long-time head of the Manchester office of Dunlop Heywood, joined Jones Lang LaSalle.
This year, DTZ replaced Erinaceous as a joint letting agent with JLL on Allied London's Spinningfields in Manchester city centre.
Erinaceous has been dogged by takeover talk and a battered share price and has failed to turnaround its fortunes via a tie-up with international network NAI.
One Manchester agent said: "It wouldn't surprise me at all if the three of them set up together. The last six months have been extremely difficult for the Manchester guys. The NAI tie-up has been over-shadowed by corporate shenanigans and there comes a time when you've got to cut your losses and get out."
Neil Cuckson, who was recently appointed to lead the Manchester office, declined to comment.
Stuart Hicks, London-based managing director of the professional services division, simply said: "Peter leaves us with our best wishes and thanks for many years' service."