What does the underwriter still do by hand after the AUS runs?
Desktop Underwriter and Loan Product Advisor return a recommendation and a list of conditions. They do not read the file. Fannie Mae's guide says "DU indicates the minimum income verification documentation required to process a loan application," and that "The lender must determine whether additional documentation is warranted." The OCC's Residential Real Estate Lending handbook puts it plainly: "Mortgage loan processing consists of information or data gathering and verification."
So the underwriter opens pay stubs, W-2s, tax returns and transcripts, bank statements, gift letters, the appraisal, title and insurance, checks each against the application and the AUS conditions, calculates qualifying income, sources large deposits, and writes the conditions the file still needs. On a distributed team with no single procedure, two underwriters can clear the same file differently.
The stakes are delivery and repurchase. If a resubmission to DU results in an ineligible recommendation, "the mortgage loan may not be delivered to Fannie Mae." For FHA loans, HUD's Handbook 4000.1 says "The Mortgagee may not accept or deny an FHA-insured Mortgage based solely on a risk assessment generated by TOTAL Mortgage Scorecard."
How do AI agents pre-screen a mortgage file and document every finding?
On MightyBot, agents classify every document in the file, extract the fields the guidelines call for, and keep a pointer to the page and position each came from. Income is calculated under your written policy for each income type, assets are traced with large deposits flagged, and the appraisal is checked for the fields and conditions your policy requires. Each value carries a confidence score, and low-confidence values route to a person.
Delivery-eligibility rules and your overlays are written as plain-English policies and compiled into checks. The agent returns a disposition, a findings memo listing every check as passed, failed or missing, and the conditions to request, before or alongside the AUS run. The underwriter decides; the file arrives with the reading done.
The record keeps the policy version, the inputs with their sources, the confidence and review on each value, and the underwriter's decision, which is what post-closing QC, investors and examiners ask to see. The same pipeline runs commercial loan underwriting and CRE lending.
What do the rules require on verification, appraisal review and adverse action?
Regulation Z's ability-to-repay rule requires a creditor to verify income and assets "using third-party records that provide reasonably reliable evidence of the consumer's income or assets," and notes that "A creditor may verify the consumer's income using a tax-return transcript issued by the Internal Revenue Service (IRS)." Fannie Mae requires the lender to "obtain a signed and complete appraisal report that accurately reflects the market value, condition, and marketability of the property."
Appraisal review has an independence rule. The Interagency Appraisal and Evaluation Guidelines say reviewers should "be independent of and insulated from any influence by loan production staff." Quality control closes the loop: the OCC expects that "the QC unit tests a sample of closed loans from all origination channels."
When a file is declined, Regulation B requires that the statement of reasons "must be specific and indicate the principal reason(s) for the adverse action," and that saying the applicant "failed to achieve a qualifying score on the creditor's credit scoring system" is insufficient on its own. A finding tied to a document and a rule is what a specific reason looks like.
