National Finance, whose core business was car finance, was placed in receivership in May 2006, with investors owed $21 million.
Ludlow's co-accused former National Finance accountant John Gray pleaded guilty to theft and false accounting charges in the Auckland District Court last year and was sentenced to nine months' home detention.
"Concluding the investigations and prosecutions of failed finance companies has been our number one priority over the past 18 months, and this sentence reflects both the seriousness and importance of this work." said SFO chief executive Adam Feeley in a press release just issued.
Feeley said one of SFO's primary objectives was to focus on cases which would make a difference to restoring investor confidence.
"Kiwi investors understand that criminal proceedings cannot restore the losses they have suffered, but equally we believe that they will take some confidence in knowing that those who have so fundamentally breached investor trust can and will be held to account."
After considering a complaint received from the Receiver, PricewaterhouseCoopers, the SFO determined that an investigation into the affairs the National Finance 2000 Limited may disclose serious or complex fraud.