The bank's financial planning division ignored repeated allegations of misconduct outlined by at least 25 clients and bank insiders known as "ferrets", who tipped off the corporate regulator in October 2008. The bank became aware of Mr Nguyen's transgressions in 2006. In September 2008 he was suspended for a month and despite an internal investigation uncovering evidence of misconduct, including excessive fees and paying kickbacks to staff for referrals, he was promoted. The whistleblowers believed he should have been sacked. One of the whistleblowers died in June 2010, six months after leaving the bank. Others still work in the industry and don't want to be identified. But one whistleblower, Jeff Morris, agreed to be identified by Fairfax Media to warn others about the perils of whistleblowing and the lack of support he got from the regulator, the Australian Securities and Investments Commission. "My advice is don't be a whistleblower," he said. "The stress is unbelievable. The impact on me and my family was horrendous.”

At least nine known victims are still waiting for full compensation from the bank. Financial Resolutions Australia is representing eight of them. It is believed 200 clients have been offered $23 million in compensation. One client, a former priest in his 70s, said the bank offered him an additional settlement of $14,000 earlier this year but he refused it, believing he was still owed $28,000. ASIC was alerted to Mr Nguyen's conduct on October 30, 2008, in a detailed fax from the whistleblowers. They warned: ‘‘The client files will basically tell the story – as they did for the internal compliance people. There is some urgency in securing them as they are being ‘cleaned up’.’’ It took ASIC 16 months to follow up on the fax. It then raided the bank’s offices to seize files. The whistleblowers sent a similar warning to senior managers at the bank. In the meantime, client funds continued to deteriorate.Retirees Mervyn and Robyn Blanch, who invested $260,000 with Commonwealth Financial Planning, had to rely on government support after their savings plummeted to $92,000.

On March 10, 2011, Mr Nguyen was banned from working as a financial planner for seven years. Seven months later ASIC imposed enforceable undertakings on the bank.The Commonwealth sent settlement offers to clients. The existence of the banning order and the comments in the order concerning Mr Nguyen’s conduct were not disclosed, with the bank stating only he had provided ‘‘inappropriate advice’’. Senator John Williams said he was concerned about the way ASIC had handled the case and would put questions to the regulator at the Senate estimates committee meeting on Tuesday. The Commonwealth was sent three pages of questions, most of which it failed to answer. Loading

It refused to comment on allegations of a potential cover-up. It did admit a ‘‘small number’’ of clients received compensation offers before its formal investigation, and some were revised to a higher figure. Don Nguyen did not respond to requests for comment left at his last known phone number.