The Public Company Accounting Oversight Board (PCAOB) has identified flaws in almost a third of the examined audits carried out by Grant Thornton US in 2010.
The watchdog said deficiencies included failures to identify or to address appropriately financial statement misstatements or to perform certain audit procedures.
The inspection reviewed forty-one Grant Thornton US audits from September 2010 until March 2011 in 21 of its 51 US offices and listed failures to comply with the Sarbanes-Oxley act in fifteen audits.
The PCAOB said in twelve cases failures were significant and related to test internal controls, problems with revenue recognition and impairments, and problems with fair value measurements and allowances for loan losses.
In a response letter to the PCAOB, Grant Thornton said it carefully considered each of the report findings and took steps to fulfil its responsibilities.