Wynyard now lives in Sydney with her family but travelled back yesterday for the appeal in Auckland.
The basis of the theft charges was that Wynyard paid money due to Aegis (another ad placement agency) to financier Marac, with which it had an invoice factoring agreement.
This arrangement, the Auckland District Court heard during Wynyard's trial, involved Marac lending money to TMC based on invoices issued to ad clients that the financier considered to be of good credit risk.
Under the deal, TMC would get cash and the amounts in the invoices would be payable to Marac.
Wynyard's lawyer Paul Davison, QC, said at the Court of Appeal yesterday that Marac had security over assets that included any invoices issued by TMC and its accounts receivable.
In November 2009, TMC entered into an agreement with Aegis for it to place adverts on its behalf after it lost industry accreditation.
Media companies would bill Aegis for the ad and the company advertising would pay TMC, which in turn would pay Aegis.
When it learned of TMC's arrangement with Aegis, Marac demanded payment of $2.4 million it was owed and the financier was paid instead of the placement agency.
Davison yesterday said that Wynyard, at the time, found herself in an "impossible legal position".
The QC argued Wynyard had two competing commercial obligations but one was secured and ended up getting the money. For the theft charges to be proven, the Crown needed to show that Wynyard had no other option than to pay the money to Aegis.
"In fact, she had no other option than to do the very same to Marac," Davison told Justices Tony Randerson, Denis Clifford and Graham Lang.
Crown lawyer Dale La Hood opposed the appeal and said Wynyard paid Marac because it was the best thing for her business rather than because she believed it was her legal obligation to do so. The three judges reserved their decision.