Deeds of trust, at the time they are recorded, identify the trustor (borrower), the beneficiary (lender), and the trustee. The trustee is usually a corporation, and holds what has been characterized as "bare legal title" to the property. The trustee has only two jobs. The first is to execute a deed of reconveyance when the loan is paid off. This document releases the trustee's "bare legal title" to the property, conveying that interest to the property owner. The second job is when requested by the lender, to handle a non-judicial foreclosure of the property.

Trustees come and go (typically out of business). Lenders contract with foreclosure companies to handle their foreclosure. The lender replaces the existing trustee with the foreclosure company it hires to handle the foreclosure. The foreclosure company becomes the "substitute trustee" as the result of their designation in a "substitution of trustee" form that is signed by the lender, naming the foreclosure company as the "substitute trustee" once that form has been recorded.