The former directors, Tenon's name for partners in the business, are understood to be preparing to set up their own firm offering audit, accounting, tax and corporate finance services in the city.
The departure of Charlie Burton, Tom Arbuckle, Raymond Clarke, David Holt and John Blair adds to the uncertainties surrounding the market's only quoted accountant, where Baker Tilly has been examining the books since July 25 and must declare its intentions by this Thursday.
RSM Tenon employs around 60 in Glasgow and around 220 in total in Scotland. It does not disclose Scottish figures but its offices in Glasgow, Edinburgh and Grangemouth are believed to turn over around £14m and be in profit. The company responded: "RSM Tenon does not comment on individual partner departures."
However when Tenon suffered a similar walk-out in its Leicester office three months ago, with three partners and a senior manager resigning to join Mazars in Nottingham, a spokeswoman said RSM Tenon "remains fully committed to its business and people in Leicester and Nottingham".
Tenon also said at the time that the Leicester ex-partners would be put on gardening leave for their six months' notice, and that Tenon would enforce a further clause banning them from working anywhere for a further three months. The company is understood to have told the Glasgow ex-directors that they will be legally restrained from working again until May 1 next year. One Edinburgh employment lawyer commented: "Nine months is not unknown for senior people, though there is a balance between protection of legitimate commercial interests and being an unjustified restraint in law."
However, if Baker Tilly decides not to proceed with its interest this week, RSM Tenon's ability to enforce the contracts may be in doubt along with its future.
One industry observer said: "If Baker Tilly do go ahead they will want to acquire the Tenon Scottish business so it could all get messy. The fact the partners have walked suggests they may believe administration is more likely." He added: "It will not have helped the financial position of the Glasgow office... there will be no pipeline of work and probably little by way of recent debt collection."
The Herald reported earlier this month that Tenon's shareholders faced being wiped out if a deal with Baker Tilly went ahead, under pressure from Lloyds Banking Group which owns 10% of the shares but all the company's £90m debt.
Last Friday the company told the stock exchange it was if an offer were made "minimal value if any" would be offered for the shares because of the company's high debt level. It added that Lloyds Banking Group "continues to be supportive of the business as the company discusses with it ways to address its high level of borrowings". That sent the shares crashing by 56% to 0.85p, a quarter of their level before the Baker Tilly talks were revealed on July 25, three weeks after the company's year end.
Industry observers say a merger could threaten up to 150 jobs in Scotland, where the two firms employ 500 between them.
Tenon has a turnover of around £200m, while Baker Tilly, seen as its only credible buyer, is just behind Tenon in eighth position in the sector's top 10 with £170m.
In February Tenon said it had entered into discussions with Lloyds to avert the "significant risk of a facility breach" over the next 12 months, highlighting a 10% fall in revenues.