Hundreds of workers will leave Coventry instead of moving to a new city centre business district.
The Royal Institution of Chartered Surveyors (RICS) is to relocate after an earlier bid to move to the new Friargate site fell through.
Instead it will move its 250 staff to premises in Birmingham.
RICS said it was "disappointed" the chance to move into a new Coventry development "did not materialise in the timescales originally envisaged".
Sean Tompkins, chief executive officer of RICS, said it aimed to complete its move from at Westwood Business Park by the end of 2017.
He said RICS considered moving to alternative premises in Coventry, relocating to Birmingham or refurbishing existing premises before deciding to move its "entire Coventry-based operations".
Friargate is to be a new 37-acre business district including 25 new buildings, 14 of which would be offices, according to its developers, and with two hotels, leisure developments and homes.
It is based around two towers, one of which is under construction and which the council will occupy.
RICS intended to take up the other but as construction had not begun, considered sharing One Friargate with the council - a plan it has now dropped.
Conservative opposition leader councillor John Blundell said the "whole development had been disappointing".
He said it was "concerning" the council was now the only tenant as their role had been hoped to "kickstart" the scheme. He said the council may have been "overly optimistic".
Coventry City Council said it had known since last month RICS intended not to move Friargate and "although we respect their decision, we remain disappointed by it."
"However, the decision does not affect our determination to deliver the wider Friargate business district which will regenerate a key area of the city centre," it added.