The US Public Company Accounting Oversight Board has revealed several audit deficiencies during its inspection of Grant Thornton's 2005 audits.
These also included one which triggered a restatement, also detailed in a report released by the PCAOB on Friday.
The body also took the firm to task on several occasions for not corroborating management's conclusions and for not providing proof that it had conducted necessary testing in this regard.
The firm, however, has retaliated strongly to parts of the findings.
In a letter to the PCAOB, the firm said: 'We strongly disagree with the use of overly broad comments such as ''failure to perform.''
'They do not adequately describe all of the relevant facts, nor do they acknowledge the extent of the procedures that were, in fact, performed by the engagement teams.'
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