According to the case brought by the Serious Fraud Office (SFO), Ludlow was found to have breached the terms of the National Finance trust deed which governed how investors' money could be spent.
He was found to have defrauded investors of $3.5 million, the SFO said.
The money included about $2.7 million in unauthorised or unsecured advances to his secondhand car companies in the Payless Car group.
There were also undisclosed related party transactions totalling over $800,000 made to an audio company, the Fiji property and land purchased for another company he owned.
SFO acting director Simon McArley said although National Finance was not the largest failed finance company, the prosecution was important to the investors who had lost money in Ludlow's venture.
"It was also one of the earliest cases that we started looking at and is probably where we started to learn some of the stuff," Mr McArley said.
He said the SFO was committed to rebuilding investor confidence in the finance industry and the prosecution showed that those guilty of taking investor money would be held to account.
Ludlow told the Herald that he had been able to work only three weeks this year as he planned and researched his court case.
He said he had had the flu during the trial but had still been expected to turn up and defend himself.
"I gave it my best shot."
Asked about the Fiji property, Mr Ludlow said he had been able to get all the investors' money back from the property. "In fact, they made money."
Ludlow said he now planned to apply for legal aid and planned to appeal against the convictions.
The investigation into National Finance was sparked after receiver PricewaterhouseCoopers lodged a complaint with the SFO in 2006.
Charges were laid against Ludlow and former National Finance accountant John Gray.
Gray was sentenced to 18 months in prison in November after pleading guilty to theft by a person in a special relationship and one charge of false accounting. He later appealed against the sentence and it was reduced to nine months home detention.
Ludlow is due to be sentenced next month.
The Deputy Registrar of Companies, Peter Barker, banned Ludlow and his co-director and former wife Carol Braithwaite from running or managing a company for 4 years in 2009.