Auditing and assurance revenues accounted for less than half of PwC’s global fees for the first time last year, underlining the shift in the professional services industry towards developing other business lines.

PwC, the biggest of the Big Four firms, will on Wednesday report global revenues of $28.2bn, up 8 per cent on last year. Its assurance division – the traditional heart of any accounting firm – accounted for 49 per cent of fees, down from 57 per cent just three years ago, as its other divisions, tax and advisory, grew far more quickly.