It failed, and Perrin went bankrupt with debts of A$28m in March 2009. Just a few months earlier, he made a dramatic confession at an emergency family meeting, revealing he had "lost everything".
"I'm going to jail, I've done a lot of bad things," Perrin cried. Ms Bricknell told the trial she thought he was going to admit being unfaithful, but he replied "No, it's much worse than that" and told her "I've lost everything".
That included the Cronin Island mansion the couple had designed and built together as a "forever home" for them and their three children, Ms Bricknell said.
Ms Bricknell, a former beautician, told the trial she thought they had no financial worries and more than A$75m in assets. She said her husband dealt with all their finances while she stayed at home looking after their three children.
She said she thought he was "dabbling" in the stockmarket and had no idea his trades totalled A$461m or that he had been increasing his debts with the bank.
The failed businessman also signed a six-page confession stating he had gone behind his wife's back for years and tricked the bank.
Perrin later denied ever writing the letter, tendered by prosecutors during the trial, claiming he was forced to sign it without realising what it was. In the letter, dated March 16, 2009, Perrin admits he has "made a lot of poor decisions".
"I have forged [Nicole's] signatures on the mortgage and all supporting documentation for two mortgages over the property during the past year," he wrote.
"I intentionally kept the paperwork for these loans and other securities from her knowledge until this time - I would always clear the PO Box and our letterbox to ensure she did not find any paperwork. I did this as I knew Nicole would never agree to mortgaging the house."
Perrin and wife Ms Bricknell made A$33m from their investment in Billabong in the late 1990s, enjoying a luxurious lifestyle for a number of years that included overseas holidays, A$10,000-a-month living expenses and the gift of a A$75,000 car to her husband, she told the trial.
Upon declaring bankruptcy, his assets were a A$100 laptop, a A$200 watch, A$1400 in shares, A$3000 in clothes, about A$16,000 in superannuation and A$30,000 cash, the Gold Coast Bulletin reported. His personal debts totalled more than A$25m and two failed private companies owed at least A$100m.
"He was a horse gambler," one friend told the Gold Coast Bulletin. "He was a pretty young guy and he had this Billabong money. He was rooting this other sheila. Nicole ended up getting kicked in the guts."
In sentencing Perrin, District Court Judge Julie Dick said he still had "no self realisation or remorse". "You seem to simply refuse to recognise that it was you who forged documents and you who caused them to be presented to the bank," Judge Dick said, the Courier-Mail reported.
"I find it disturbing that you [submitted today] that your wife knew of and approved of the loans. This flies in the face of the confession you signed. I find you did make that confession and it was true."
Commonwealth Bank remains about A$9m out of pocket, as Ms Bricknell fought the bank in court to keep the Cronin Island mansion. She sold it for A$6.1m in 2012.
In January, Ms Bricknell posted a New Year message on Facebook describing the past nine years as a "nightmare". "I will stay strong, work hard and provide everything I can for my children," she wrote.
"I'm so proud of them and their strength and courage throughout this nightmare nine years. It's been horrific and they have generally been amazing. We've had ups and many many downs, but we are survivors.
"I love them so deeply and am beyond proud of my three."
Judge Dick said it was "inevitable" Perrin would be found guilty given the "considerable evidence" against him. She said Perrin's offending struck at the heart of commercial integrity, and his good standing in the community and lack of criminal history were all the hallmarks of white-collar crime.
"You turned to these criminal activists to stay afloat," she said. Perrin, who was unresponsive during his sentencing, will be eligible for parole in late 2020.
