PwC and the partner who signed off on the accounts of BHS have been fined £6.5m and £325 over the scandal by the Financial Reporting Council.
Steve Denison admitted misconduct over the 2014 audit of BHS and the Taveta Group, which controls Topshop, was also banned from the profession for 15 years.
In 2015 Mr Denison signed off the BHS accounts as a going concern, just days before it was sold for £1.
BHS collapsed in 2016 with the loss of 11,000 jobs and a pension deficit of £571m.
The FRC said both had admitted “misconduct”, with PwC acknowledging “serious shortcomings with this audit work”.
In a statement the industry giant said: “We are sorry that our work fell well below the professional standards expected of us and that we demand of ourselves,” the company said.
“At its core this is not a failure in our audit methodology, the methodology simply was not followed.”
It added that the audit failings “did not contribute to the collapse of BHS” and that it had overhauled its monitoring procedures.
Mr Denison left the audit firm this month after nearly 33 years there.
The fines were reduced by 35 per cent from £10 million to £6.5 million and from £500,000 to £325,000 respectively for early settlement.
The settlement agreement was approved by The Right Honourable Sir Stanley Burnton, independent Tribunal member.