Where a power to sell real property is given to a mortgagee, or other encumbrancer, in an instrument intended to secure the payment of money, the power is part of the security and vests in any person who by assignment becomes entitled to payment of the money secured by the instrument. The power of sale may be exercised by the assignee if the assignment is duly acknowledged and recorded.
Source:
Section 2932.5, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=CIV§ionNum=2932.5..