What Desktop Underwriter Does for Your Loan
Desktop Underwriter serves as Fannie Mae's automated decision-making system for mortgage applications. When your lender submits your loan information, DU analyzes your credit history, income, assets, down payment, and debt-to-income ratio to determine whether you qualify for a Fannie Mae loan.
DU doesn't just check boxes on individual requirements. Instead, it weighs all risk factors together. Say you have a lower credit score but substantial cash reserves and stable employment history. DU might approve your loan because the strong factors offset the weaker credit score.
The system evaluates mortgage delinquency risk using statistically validated data. It identifies patterns that predict whether borrowers will make their payments on time. This comprehensive analysis often allows approvals for borrowers who might not qualify under rigid manual underwriting standards.
How the DU Process Works
Your lender enters your loan application data into their system, pulls your credit report, and submits everything to DU. The system returns two key reports within minutes.
The DU Underwriting Findings report gives the overall recommendation and lists specific conditions your lender must verify. This might include requirements like "verify employment within 10 days of closing" or "obtain two months of bank statements."
The Underwriting Analysis report provides detailed information similar to what appears on manual underwriting forms. Your lender uses both reports to complete your loan file and ensure all conditions are met before closing.
If your loan information changes after the initial DU submission, your lender must update the file and resubmit it. Major changes like a job switch, additional debt, or property changes require a fresh DU review.
What Documents Support Your DU Approval
DU approval doesn't eliminate documentation requirements. Your lender must still collect and verify all supporting paperwork specified in the DU findings report.
Common verification requirements include recent pay stubs, tax returns, bank statements, and employment verification letters. The specific documents depend on your income type, asset sources, and any risk factors DU identifies.
Your lender must confirm that credit report information matches your actual credit history. They review for errors, missed derogatory items, or contradictory information that DU might not have detected.
All documentation must meet Fannie Mae's age requirements as of your loan closing date. If documents expire between DU approval and closing, your lender must obtain updated versions.
Why DU Uses This Comprehensive Approach
Traditional underwriting often rejected borrowers based on single factors like credit scores or debt ratios. DU recognizes that mortgage performance depends on the interaction between multiple risk elements.
A borrower with a 620 credit score might get approved if they have 20% down, substantial reserves, and stable income. The strong compensating factors reduce the overall risk despite the lower credit score.
This approach allows Fannie Mae to serve more borrowers while maintaining loan quality. The system uses decades of mortgage performance data to identify which combinations of factors lead to successful loans.
DU also ensures consistent treatment across all borrowers. The automated system applies the same standards regardless of location, lender, or borrower demographics.
When Things Get Complicated
DU approval doesn't guarantee your loan will close successfully. Your lender must still verify that all conditions are met and that you continue to qualify through closing.
If you change jobs, take on new debt, or your financial situation changes after DU approval, your lender may need to resubmit your file. Significant changes could result in a different recommendation or additional conditions.
Some loans receive "refer" recommendations, meaning DU couldn't make an automated decision. These loans require manual underwriting using Fannie Mae's traditional guidelines B3-6-01: General Information on Liabilities.
Credit report errors can cause problems even with DU approval. If your lender discovers incorrect information that DU didn't catch, they must investigate and potentially decline the loan despite the automated approval.
Post-closing resubmissions create another potential complication. If your lender needs to resubmit your loan to DU after closing and receives an ineligible recommendation, Fannie Mae won't purchase the loan.
Timing and File Management
Your lender must submit your loan to DU before closing, but they can also submit it earlier in the process for preliminary approval. Many lenders run DU during pre-approval to give you confidence in your buying power.
DU loan files don't stay in the system forever. Files are archived 270 days after the last update or 540 days after creation, whichever comes first. Construction-to-permanent loans get the full 540 days regardless of activity.
Once archived, files cannot be restored. If your lender needs to resubmit an archived loan, they must create an entirely new file subject to current DU policies and guidelines.
This archival policy keeps the system running efficiently but means lenders must manage their loan pipelines carefully to avoid losing approved files.
Your Lender's Ongoing Responsibilities
DU approval doesn't remove your lender's obligation to use sound underwriting judgment. They must still evaluate whether your loan makes sense and whether you can realistically afford the payments.
Lenders must verify all data they submit to DU and ensure nothing was omitted that might have changed the recommendation. They're responsible for catching errors, inconsistencies, or missing information.
Your lender must also ensure the final loan terms match exactly what DU approved. Changes to loan amount, interest rate, or property value may require resubmission and could affect the approval.
Even with automated approval, lenders bear full responsibility for loan quality and compliance with all applicable laws and regulations. DU doesn't evaluate legal compliance issues like qualified mortgage requirements.
References
For the official guidelines, see B3-2-01: General Information on DU in the Fannie Mae Selling Guide.
Mortgage guidelines change. Stay current.
Fannie Mae and Freddie Mac update their rules several times a year. Get notified when changes affect your mortgage eligibility, required documents, or loan terms.
No spam · Unsubscribe anytime
Original Fannie Mae Guideline Text
B3-2-01, General Information on DU (07/02/2025)
Overview
Fannie Mae’s underwriting policies include an evaluation of the borrower’s (or spouse’s to the extent required by applicable law) equity investment, credit history, liquid reserves, reliable and recurring income, and the cumulative effect that these and other risk factors have on mortgage loan performance. Fannie Mae’s underwriting policies enable the lender to consider various scenarios in evaluating a borrower’s willingness and capacity to repay the mortgage loan. The lender must confirm that information provided by the borrower during the loan application process is accurate and complete; include documentation in the loan file that supports the lender’s assessment of the borrower’s credit history, employment and income, assets, and other financial information used for qualifying; conduct a comprehensive risk assessment of each mortgage loan application; and render a decision to either approve or decline the mortgage loan application.
Fannie Mae offers lenders two options for conducting a comprehensive risk assessment–automated underwriting through DU or manual underwriting. Both methods include an evaluation of the borrower’s equity investment, credit history, liquid reserves, reliable and recurring income, and the cumulative effect that these and other risk factors have on mortgage loan performance.
DU evaluates mortgage delinquency risk and arrives at an underwriting recommendation by relying on a comprehensive examination of the primary and contributory risk factors in a mortgage application. (See
) It analyzes the information in the loan casefile to reach an overall credit risk assessment to determine eligibility for delivery to Fannie Mae.
No one factor determines a borrower’s ability or willingness to make their mortgage payments. DU identifies low-risk factors that can offset high-risk factors. When several high-risk factors are present in a loan casefile without sufficient offsets, the likelihood of serious delinquency increases.
DU conducts its analysis uniformly, and without regard to race, gender, or other prohibited factors. DU uses validated, statistically significant variables that have been shown to be predictive of mortgage delinquency across all groups.
DU does not evaluate a loan’s compliance with federal and state laws and regulations including, without limitation, a loan’s potential status as a qualified mortgage under applicable laws and regulations. Lenders bear sole responsibility for complying with applicable laws and regulations, and these compliance obligations may not be imposed upon or shared by Fannie Mae.
Underwriting with DU
Lenders must enter loan data (including data from the Form 1003) in their loan origination system or in the DU user interface before submitting for underwriting. A credit report must also be obtained. Loans may be submitted to DU before or after the closing of the mortgage loan; however, the first submission to DU for underwriting purposes must occur before closing of the mortgage loan.
When the mortgage loan or borrower information changes and it no longer matches the information used when the loan casefile was last underwritten with DU, the lender must update the data and resubmit the loan casefile to DU. Exceptions are specified in
.
When the loan casefile is resubmitted to DU after closing and prior to delivery to Fannie Mae, the lender is responsible for ensuring that:
all information provided in the final submission to DU matches the terms of the closed loan;
the loan complies with the requirements specified in ;
the loan delivery data matches both the closed loan and the final data submitted to DU; and
the loan casefile receives an eligible recommendation from DU on the final submission.
The lender may request a new credit report after closing when the loan casefile is resubmitted and, as with all loan casefiles, must comply with the Fair Credit Reporting Act with regard to the purpose and nature of the inquiry. If the new credit report contains information that is different than the information used to prepare the final loan application that was signed by the borrower at closing, the loan application must be updated. (Borrower signature(s) are not required due to the update occurring post-closing.) The lender must include both the final signed and the updated unsigned loan applications in the loan file.
Note: The credit report must meet the allowable age of documents as of the note date. If the credit report expired prior to the note date and the loan casefile is being resubmitted to DU, a new credit report must be requested.
In certain instances, the lender may not be able to access the original DU loan casefile for resubmission purposes. Lenders may create a new loan casefile in DU after closing to ensure that all information in the final DU submission matches the terms of the closed loan, provided all of the following conditions are met:
the above lender responsibilities are met, including the updating of the final loan application, if applicable;
the loan has not yet been delivered to Fannie Mae;
the loan has the same information (for example, the same borrower(s) and property) as had previously been underwritten through DU prior to closing using another loan casefile, and that loan casefile received an eligible recommendation from DU;
the lender retains the DU Underwriting Findings Report from the original loan casefile ID in the loan file;
the DU submission using the new loan casefile occurs no more than 60 days after closing (based on the note date) or 18 months after initial closing for single-closing construction-to-permanent loans (described in ); and
as stated above, when a new credit report is requested, the lender complies with the Fair Credit Reporting Act.
If the resubmission to DU results in an “ineligible” recommendation, the mortgage loan may not be delivered to Fannie Mae.
Note: If the quality control function is performed before delivery, the above requirements apply. If quality control is performed after delivery, see Chapter D1-3, Lender Post-Closing QC Mortgage Review.
DU issues two types of reports:
The DU Underwriting Findings report summarizes the overall underwriting recommendation and lists the steps necessary for the lender to complete the processing of the loan file. This is typically the first report viewed by an underwriter or a loan officer after the loan casefile has been underwritten with DU. This report is described in .
The Underwriting Analysis report contains much of the same information requested on the Uniform Underwriting and Transmittal Summary ( ).
Each time a loan casefile is resubmitted to DU, the information in these reports is updated with information from the most recent submission. The date and time of each submission are recorded on each report, along with the unique loan casefile ID.
Loan Casefile Archival Policy
DU loan casefiles are archived and no longer retained in DU from the earlier of
270 days from the date on which the loan casefile was last updated, or
540 days from the date on which the loan casefile was created.
Loan casefiles for single-closing construction-to-permanent transactions (identified in DU as a Construction-to-Permanent Closing Type of Single-Closing), will only be archived using 540 days from the date on which the loan casefile was created.
These time frames are intended to ensure that the total volume of loans in the system is at a manageable level, reducing the time required by DU to search for and retrieve loan casefiles
After a loan casefile is archived from DU, it cannot be restored. If a loan casefile that has been archived must be re-underwritten, a new loan casefile must be created and submitted to DU. The loan casefile will be subject to the policies in effect for the current version of DU. Fannie Mae is not responsible for retaining loan casefiles for the lender.
DU Underwriting Recommendations
The following topics describe the underwriting recommendations returned by DU:
.
.
.
.
General Requirements for Lenders
When underwriting loans with DU, the lender must:
employ prudent underwriting judgment in assessing whether a loan casefile should be approved and delivered to Fannie Mae;
confirm the accuracy of the data it submits, making sure that it did not fail to submit any data that might have affected the DU recommendation had it been known;
ensure that the loan complies with all of the verification messages and approval conditions specified in the DU Underwriting Findings report;
apply due diligence when reviewing the documentation in the loan file;
review the credit report to confirm that the data that DU evaluated with respect to the borrower’s credit history was accurate and complete;
determine if there is any potentially derogatory or contradictory information that is not part of the data analyzed by DU; and
take action when erroneous data in the credit report or contradictory or derogatory information in the loan file would justify additional investigation or would provide grounds for a decision that is different from the recommendation that DU delivered.
For example, if a foreclosure was reported in the credit report but was not detected by DU (that is, it was not referenced in any verification messages), the lender must determine if the loan complies with the applicable guidelines (see
).
See the
for a number of helpful resources.
