Quick answer
Automated underwriting is software that evaluates a mortgage application against an agency’s risk model and returns a recommendation within minutes. Fannie Mae’s Desktop Underwriter (DU) and Freddie Mac’s Loan Product Advisor (LPA) handle most conventional loans; FHA files are scored by FHA’s TOTAL Mortgage Scorecard, and USDA uses its Guaranteed Underwriting System.
Key facts
How it weighs a file
Instead of applying fixed cutoffs one at a time, the system looks at the whole file together: credit score and history, debt-to-income ratio, loan-to-value, reserves, loan type and property. Strength in one area can offset weakness in another, which is why DU can approve a DTI up to 50%, while a manually underwritten Fannie Mae loan starts at 36%, and why Fannie Mae sets no fixed minimum score for DU files. The findings also list what the lender must verify before closing.
When the answer is “refer”
A DU recommendation of Approve/Eligible means the loan meets Fannie Mae’s risk standards, subject to verification. A Refer with Caution, or a Refer from FHA’s scorecard, isn’t a denial: where the program allows, the lender can send the file to manual underwriting, or restructure the loan with a bigger down payment or a paid-off debt and resubmit. Since the result depends on what’s in your file, errors on your credit report matter; check them before applying, as the pre-approval guide explains.
Related terms
- Underwriting, the full review process
Sources
- Fannie Mae Selling Guide B3-6-02 — Fannie Mae maximum DTI, Desktop Underwriter loans; Fannie Mae maximum DTI, manually underwritten loans (Apr 2, 2025)
- Fannie Mae: Desktop Underwriter
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