Global management consultancy Bain & Company has admitted to "significant errors of judgement" in the work it did for the SA Revenue Service, for which it was sharply criticised by retired Judge Robert Nugent in the final SARS commission report.
In a statement, Bain said that it was "shocked and saddened by our involvement with SARS".
"We let down our clients, our people, our alumni and our firm. Most of all, we have let down South Africa."
Nugent delivered the commission's final 199-page report to President Cyril Ramaphosa last week.
The commission was set up to probe the state of tax administration and governance at the revenue collection agency.
Among the report's findings was that the local office of Bain worked in concert with axed SARS commissioner Tom Moyane in a what the report's authors called a "premeditated offensive".
"We think what occurred can fairly be described as a premeditated offensive against SARS, strategised by the local office of Bain & Company, located in Boston, for Mr Moyane to seize SARS, each in pursuit of their own interests that were symbiotic, but not altogether the same," states the report.
"Mr Moyane’s interest was to take control of SARS. Bain’s interest was to make money. This was not a plan for mere succession in public service."
Moyane has consistently denied that he did anything wrong.
Bain said that while it exhibited "various lapses in leadership and governance" in its work for SARS, it did not accept that its local representatives knowingly participated in an effort to damage the agency, describing its role as that of an "unwitting participant".
"We understand the justifiable anger felt by South Africans, and are deeply sorry for what has happened to SARS and for our involvement.
"Bain does not, however, accept that its representatives knowingly participated in an effort to damage SARS," it said.
"Bain made many mistakes in relation to SARS, but the firm had no motive, monetary or otherwise, to damage SARS, and did not set out to do so."
The group - which said its understanding of SA politics was naive - also announced it had appointed Bain partner John Senior as the group's SA head from January 2019, and created an advisory board to guide its future work.