Stonemartin managing director Colin Peacock has quit the managed offices business, after it abandoned plans for a UK network.
The AIM-quoted plc currently operates the IoD Hub at Birmingham's One Victoria Square, plus other city centre schemes in London, Reading, Bristol and Manchester.
However, Stonemartin formally confirmed to the Stock Exchange yesterday that it was "unlikely" to acquire new premises, in the short to medium-term.
Peacock's resignation means the business will now be managed by chief operating officer Graham Ede, and sales director Tim Worboys.
Stonemartin's buildings have been regularly praised for their quality, the provision of meeting rooms and conference space, and the high level of support services.
Birmingham's IoD Hub is regarded as the most sophisticated managed office scheme in the city centre.
However, there have been signs of internal friction since Spring 2007, when it was revealed that Stonemartin's institutional backers wanted to sell its office portfolio, and retain the operating company.
The 430,000 sq ft of Grade A space was then estimated to be worth between £160 million and £200 million, although such calculations were made well before the credit crunch surfaced in late-summer.
At the time, Mr Peacock expressed public frustration that the fit-out of Stonemartin's latest scheme, in Bristol, had been delayed by several months, because of the mooted portfolio sell-off.
Mr Peacock's business model was to provide high-quality managed or serviced offices, on prime city centre sites, of around 100,000 sq ft, and on floor-plates of 20,000 sq ft wherever possible.
His swift departure would suggest that the pressure of the institutional shareholders has persuaded his fellow directors to put expansion on hold.