Types of automated underwriting systems
The useful way to sort them is by who writes the rules and which loans the rules cover. Five buckets cover the 2026 market.
Five buckets
Agency underwriting serves conventional agency production. It will not run your overlays or Non-QM.
Government AUS and scorecards. GUS for USDA. FHA TOTAL and VA run inside agency underwriting. Government box only.
Proprietary single-investor engines. Investor-built. One rulebook. Useful if you sell to that investor. Painful if you sell to twelve.
Document-AI adjacent tools. Extraction and income tools. They read. They do not decide. They show up in lists of automated underwriting systems because buyers mix up reading files with deciding files.
Configurable non-agency automated underwriting system. AUS is this type. Lenders who write their own box, including jumbo and Non-QM across many investors. The only limit is what you refuse to write as a rule.
Agency AUS
Agency underwriting is the standard. It underwrites to agency guidelines you cannot edit. Findings language is shared across the industry.
Government AUS
GUS is USDA’s own AUS. FHA TOTAL and VA run inside agency underwriting. Same idea: a published box, not yours.
Proprietary single-investor engines
Some investors encode their own guidelines and require sellers to hit that engine. That is an AUS for one credit box.
Document-AI adjacent tools
These are not types of AUS. They read files. They do not decide files.
Configurable non-agency AUS
You write the rules. The engine returns findings on Non-QM, jumbo, business purpose, and portfolio programs, including multi-investor overlays. This is the type LoanPASS built.
What is an automated underwriting system
Agency vs non-agency AUS
AUS vs document AI
Best mortgage underwriting software
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