The group made 14 loan applications between August 2015 and October 2016 claiming they were employees of Martin’s company.
Serious Fraud Office director Karen Chang said the scheme was a deliberate effort to avoid lending restrictions.
“New Zealanders invest heavily in property, and mortgages are a key part of the process. Lending restrictions protect both banks and those who are borrowing, as well as the wider economy,” she said.
“Offending of this nature breaches the trust between bankers, mortgage brokers and customers, which can ultimately impact the ability of future borrowers to secure loans.”
On Wednesday, Martin was sentenced to four years in prison and Joshua Grant was sentenced to 28 months.
Sian Grant pleaded guilty in March and was sentenced to 12 months’ home detention.
Cotter pleaded guilty last year and was sentenced to nine months’ home detention which was to begin last January.