PricewaterhouseCoopers, KPMG, Ernst & Young and Deloitte have shed one in five Scottish staff in the past two years.
More than 500 fee-earners have left their jobs in Scotland since 2001.
And entrants have also been hit hard; trainee numbers have been slashed by a third.
PwC alone has reduced the number of people it employs in Scotland by 250 since 2001.
It has reduced its Scottish payroll by a quarter and KPMG’s numbers are down by 20%.
The research may be seen as a sign of a weakening Scottish economy.
And the dearth of corporate transactions in the £10m-plus bracket is thought to have hit the big accountancy firms hard.
The research was carried out by CA magazine, the journal of the Institute of Chartered Accountants of Scotland.
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