There are a number of private trustee companies in South Australia, each of which is authorised by a special Act of Parliament to administer deceased estates and to conduct trustee and agency businesses generally.

Private trustee companies charge a rate that is generally slightly higher than that of the Public Trustee. The rates charged vary from company to company. Reduced commissions are charged in certain cases. Some trustee companies charge for preparing wills. Trustee companies will act jointly with a private executor. People considering having a trustee company prepare a will and administer an estate should ask what the charges are.