When you apply for a mortgage, one of the first things your lender does is run your application through an automated underwriting system, or AUS. This software evaluates your loan profile against program guidelines and returns a recommendation before any human underwriter looks at the file. Understanding what AUS is, how it works, and what its findings mean can help you navigate the mortgage process with fewer surprises.
What Is an Automated Underwriting System?
An automated underwriting system is software that analyzes mortgage loan applications using algorithms. The lender inputs your financial data, credit score, income, assets, debts, loan amount, and property details, and the system evaluates it against the guidelines for the loan program you are applying for. Within minutes, it returns a findings report telling the lender whether the loan is likely to meet investor standards.
AUS does not make the final lending decision. It produces a recommendation that a human underwriter then uses as the framework for their review. Think of it as a first-pass filter: if the automated system approves the loan, the underwriter focuses on verifying documentation and clearing conditions. If it does not approve, the lender has to determine whether other options exist.
Almost every conventional, FHA, and VA loan originated today goes through AUS. It is not optional for most loan programs, investors who buy loans on the secondary market generally require an automated approval as part of the loan’s salability standards.
The Two Main AUS Systems: DU and LP
There are two primary automated underwriting systems used in the U.S. mortgage market:
- Desktop Underwriter (DU), Fannie Mae’s system, the most widely used. DU is the default for most conventional loans and is also used to evaluate FHA and VA applications against those programs’ guidelines.
- Loan Product Advisor (LP), Freddie Mac’s system, used for conventional loans backed by Freddie Mac guidelines.
| Desktop Underwriter (DU) | Loan Product Advisor (LP) | |
|---|---|---|
| Owner | Fannie Mae | Freddie Mac |
| Used for | Conventional, FHA, VA loans backed by Fannie Mae guidelines | Conventional loans backed by Freddie Mac guidelines |
| Output | Approve/Eligible, Refer, Refer with Caution, Out of Scope | Accept, Caution, Ineligible |
| Key difference | Wider adoption; more lenders run DU by default | Can sometimes approve files DU declines; worth running both |
Most borrowers never interact directly with DU or LP, the lender runs the file on their behalf. But knowing which system is being used, and that both options exist, matters in borderline situations. A file that gets a Refer from DU may get an Accept from LP, since the two systems use different algorithms and weight factors differently. An experienced lender will run both when the situation warrants it.
What Does AUS Actually Evaluate?
AUS does not apply simple pass/fail rules to individual numbers. It evaluates the overall risk profile of the loan by weighing multiple factors together:
- Credit score and credit history: Payment history, derogatory events, length of credit, and types of accounts.
- Debt-to-income ratio (DTI): Your total monthly debt obligations divided by your gross monthly income.
- Loan-to-value ratio (LTV): Your loan amount relative to the property’s appraised value.
- Employment and income stability: Length of employment, income type (W-2, self-employed, rental), and consistency.
- Assets and reserves: Funds available for the down payment, closing costs, and post-close reserves.
- Property type and occupancy: Whether the property is a primary residence, second home, or investment property, and its type (SFR, condo, multi-unit).
Because the system evaluates all factors together, a weakness in one area can sometimes be offset by strength in another. A borrower with a lower credit score but a large down payment and substantial reserves may still receive an approval that a borrower with a higher score and minimal assets does not. This is why the same two borrowers can get different AUS outcomes even with similar credit profiles.
AUS Findings: What Each Result Means
When AUS evaluates a file, it returns one of several possible findings. Here is what each means in practice:
| Finding | What It Means | What Happens Next |
|---|---|---|
| Approve/Eligible (DU) Accept (LP) | Loan meets automated approval criteria; risk is acceptable | Underwriter reviews the file and conditions for standard documentation |
| Refer (DU) Caution (LP) | Automated system cannot approve; does not necessarily mean denial | May proceed to manual underwrite if borrower has compensating factors; lender discretion applies |
| Refer with Caution (DU) | High risk profile; automated system flags significant concerns | Most lenders will not proceed; alternative loan types may be explored |
| Out of Scope / Ineligible | Loan does not meet program parameters (e.g., loan amount, property type) | Loan must be restructured or submitted under a different program |
The most important finding for most borrowers is Approve/Eligible (DU) or Accept (LP). This is the green light that allows the loan to move forward through standard underwriting. The conditions attached to an automated approval are typically documentation-based: verifying employment, sourcing down payment funds, confirming the appraisal, and similar items.
A Refer finding creates more complexity. It does not mean the loan is denied, but it does mean the lender must decide whether to proceed with a manual underwrite or explore alternative loan options. Not all lenders do manual underwrites, which is one reason that working with a lender experienced in these situations matters.
What Is a Manual Underwrite?
A manual underwrite is the traditional alternative to an automated approval. Instead of relying on an algorithm, a human underwriter reviews the full loan file and applies program guidelines directly. Manual underwrites are more time-intensive and require more documentation, but they allow an underwriter to see context that AUS cannot.
For example, AUS does not know that your income dropped two years ago because of a medical event and has since fully recovered. It just sees a gap in employment. A manual underwriter can review that explanation, weigh the supporting documentation, and make a judgment call that the algorithm cannot.
FHA loans explicitly allow manual underwrites under specific conditions. Borrowers who receive a Refer through DU may qualify for FHA financing through a manual underwrite if they have compensating factors, typically low DTI, minimal debt, no recent late payments, and a clear explanation of any derogatory history. Conventional loans rarely allow manual underwrites, though exceptions exist.
What to Do If You Get a Refer
A Refer finding from AUS is not the end of the road. Depending on your situation, several paths may be available:
- Run LP if only DU was run. If your lender submitted only to DU, ask them to run Loan Product Advisor. The different algorithm may return an Accept.
- Explore FHA financing. If a conventional loan is not workable, FHA’s guidelines are more forgiving and its manual underwrite pathway is well-defined.
- Address the specific issue. The Refer findings report identifies which factors triggered the result. Paying down a credit card balance, correcting an error on a credit report, or documenting income more clearly can sometimes convert a Refer to an Approve on resubmission.
- Consider non-QM. Non-qualified mortgage loans bypass AUS entirely and use lender-specific underwriting criteria. They typically carry higher rates, but they serve borrowers whose profiles do not fit conventional or government-backed guidelines.
- Work with a lender who does manual underwrites. Not all lenders will proceed with a manual underwrite even when it is technically allowed. Finding one that does, and that has experience with the process, is important.
How AUS Connects to the Pre-Approval Process
When JVM issues a pre-approval, the loan application has already been run through AUS. This means the pre-approval is not just an estimate based on your stated income and credit score, it reflects an actual automated underwriting finding against the program guidelines for the loan you are applying for.
This matters when you make an offer. A pre-approval backed by an AUS finding carries more weight with listing agents and sellers than a pre-qualification that has not been run through any automated system. It means the lender has already evaluated your file against the standards that will ultimately determine whether the loan funds.
Frequently Asked Questions
What is AUS in mortgage?
AUS stands for Automated Underwriting System. It is software used by mortgage lenders to evaluate a loan application against program guidelines and return an automated approval recommendation. The two primary systems are Desktop Underwriter (DU), owned by Fannie Mae, and Loan Product Advisor (LP), owned by Freddie Mac.
What does it mean when a loan gets an AUS approval?
An AUS approval means the automated system determined the loan meets program guidelines and the risk profile is acceptable. It does not mean the loan is fully approved. A human underwriter still reviews the full file, verifies documentation, and issues conditions that must be satisfied before closing.
What is the difference between DU and LP?
Desktop Underwriter (DU) is Fannie Mae’s system. Loan Product Advisor (LP) is Freddie Mac’s. Both evaluate conventional loan applications but use different algorithms. A file that gets a Refer from DU sometimes gets an Accept from LP. A good lender will run both when the situation warrants it.
What happens if AUS says Refer instead of Approve?
A Refer means the automated system could not approve the loan, but it is not an automatic denial. The file may be eligible for a manual underwrite depending on the loan type and compensating factors. FHA loans in particular allow manual underwrites for borrowers who Refer through DU but meet certain criteria.
What factors does AUS evaluate?
AUS evaluates credit score and history, debt-to-income ratio, loan-to-value ratio, employment and income stability, assets and reserves, and property type. It weighs these factors together as an overall risk profile rather than applying hard cutoffs to each individually.
Can you get a mortgage without an AUS approval?
Most conventional lenders require an automated approval before funding. FHA and VA loans allow manual underwrites for borrowers who do not receive an automated approval if they meet compensating factor requirements. Non-QM loans bypass AUS entirely and use lender-specific criteria, typically at higher rates.
Does running AUS affect my credit score?
No. Running AUS uses the credit data already pulled by the lender. What may affect your score is the initial hard inquiry when the lender pulls your credit. Multiple mortgage inquiries within a short window, typically 14 to 45 days depending on the scoring model, are usually counted as a single inquiry.
Questions About Your AUS Findings?
AUS findings shape the entire path of your loan from pre-approval through closing. Understanding what your findings report says, and what options exist if the result is not straightforward, is something JVM Lending helps borrowers navigate every day.
Contact JVM Lending today to get a full pre-approval with AUS findings and understand exactly where your loan stands.
