Gray had pleaded guilty to theft and false accounting charges in the Auckland District Court in 2010 and was sentenced to nine months' home detention.
Ludlow said the fraudulent transactions were at the initiative of Gray and any fraud was his fraud.
He also said the District Court Judge Josephine Bouchier erred throughout her judgment by providing insufficient reasons for her verdict.
He said the verdict of the judge was unreasonable and could not be supported having regard to the evidence.
Another director of the company, Anthony David Banbrook, was sentenced to eight and a half months' home detention and ordered to pay $75,000 reparation when he appeared in the High Court at Auckland earlier this month.
He had earlier pleaded guilty to signing a company prospectus that included untrue statements.
In Ludlow's appeal, the Crown pointed to a document signed by Ludlow, which was written to support Banbrook in his sentencing, that the Crown described as a "brutally frank mea culpa".
The note said Ludlow and Gray had concealed their offending from Banbrook with respect to the misuse of investor funds.
"I confirm that I did so," the note said.
In a written judgement released today Justices Simon France, Douglas White and Raynor Asher said there was there was nothing to indicate the affidavit was not true.
They also disagreed Judge Bouchier had erred in providing insufficient reasons for her verdict.
"...the reasons while on occasions brief, accurately referred to the key facts and law and explained why the judge reached her decision on each count."
They ruled the judge was correct in her verdict.
As well as the SFO case, Ludlow pleaded guilty to eight charges brought by the Financial Markets Authority (FMA) for misleading investors and making false financial statements.
As a consequence, he had nine months added to his sentence earlier this year.
Ludlow will appeal against both the SFO and FMA sentences at a later date.
National Finance, whose core business was car finance, was placed in receivership in May 2006, with investors owed $21 million.
Some investors have recovered 49 cents in the dollar, although others have been left completely out-of-pocket.