Desktop Originator (DO)

Updated 2026-05-18

Desktop Originator (DO) is a system that provides sponsored mortgage brokers with access to Fannie Mae's Desktop Underwriter (DU). It serves as the interface through which mortgage brokers can utilize DU's automated underwriting capabilities.

Role in Wholesale Lending

DO is particularly relevant in the Wholesale Lending model, where mortgage brokers originate loans and then sell them to larger lenders. Through DO, brokers can submit loan casefiles for DU underwriting to their sponsoring wholesale lenders.

Key Features and Functions

• Broker Access to DU: DO enables mortgage brokers to submit loan casefiles for DU underwriting.
• Wholesale Resources: Fannie Mae provides specific resources for DO users, including guidance on setting up wholesale accounts, searching for sponsoring lenders, job aids for common tasks, and broker registration forms.
• Support and Integration: Mortgage brokers using DO are encouraged to contact their sponsoring wholesale lender for information regarding DU release notes and for technology integration support.

Distinction from Desktop Underwriter (DU)

The primary distinction between DO and DU is their intended users and access points:

• Desktop Underwriter (DU): The core automated underwriting system itself, used directly by approved Fannie Mae sellers (lenders).
• Desktop Originator (DO): The platform that provides sponsored mortgage brokers (third-party originators or TPOs) with access to DU's capabilities.

In essence, DU is the engine for automated underwriting, and DO is the specific vehicle that allows mortgage brokers to access and utilize that engine.