aus-integration

What this skill does

# AUS Integration Workflow Design

Design the integration workflow between a mortgage LOS and Automated Underwriting Systems (AUS): Fannie Mae Desktop Underwriter (DU), Freddie Mac Loan Product Advisor (LP), and USDA Guaranteed Underwriting System (GUS). Covers submission setup, findings interpretation, documentation requirements, and resubmission workflows.

## AUS System Overview

| AUS | Owner | Programs | Access Method |
|-----|-------|---------|--------------|
| Desktop Underwriter (DU) | Fannie Mae | Conventional Fannie, FHA, VA (via integration), USDA (via integration) | Fannie Mae Connect API + Selling & Servicing Guide |
| Loan Product Advisor (LP) | Freddie Mac | Conventional Freddie, FHA (via integration) | Freddie Mac API + Selling & Servicing Guide |
| GUS | USDA Rural Development | USDA Section 502 Guaranteed Rural Housing | GUS portal (direct entry or LOS integration) |

---

## Section 1: Connection Setup

**DU connection configuration:**

| Configuration Item | Required Value |
|--------------------|---------------|
| Fannie Mae Seller/Servicer ID | [Client's Seller/Servicer number] |
| DU API credentials | Obtained through Fannie Mae Connect; stored securely in LOS credential vault |
| Submission format | MISMO 3.4 XML (current standard) |
| Response format | DU findings XML + PDF findings report |
| Environment | Production (separate from test/sandbox) |
| Network access | Fannie Mae whitelists IP addresses — provide production IPs to Fannie Mae |

**LP connection configuration:**

| Configuration Item | Required Value |
|--------------------|---------------|
| Freddie Mac Seller/Servicer ID | [Client's Seller/Servicer number] |
| LP API credentials | Obtained through Freddie Mac Loan Advisor Suite portal |
| Submission format | MISMO XML or ULDD format |
| Response format | LP feedback certificate XML + PDF |
| Environment | Production |

**GUS connection configuration:**

| Configuration Item | Description |
|--------------------|-------------|
| USDA GUS access | GUS web portal or LOS-GUS integration (not all LOS have native GUS API) |
| USDA Business Partner ID | Client's USDA lender ID |
| If LOS integration not available | Manual GUS submission with copy of findings stored in LOS document management |

**Credential management:**
- AUS credentials stored in LOS encrypted credential vault (never in plain text config files)
- Credentials rotated per AUS provider policy (typically annually)
- Separate sandbox/test credentials for pre-production testing
- Service account credentials (not tied to individual employee)

---

## Section 2: Submission Workflow

**When to submit to AUS:**

| Event | Action |
|-------|--------|
| Borrower has expressed intent to proceed and application is complete | Initial AUS submission |
| Any of the following data changes | Resubmission required (see Section 4) |
| Final submission before underwriting | Submit current AUS run; findings in file |

**Loan setup before AUS submission:**

1. Confirm loan program (Conventional Fannie / Conventional Freddie / FHA / VA / USDA / other)
2. Map program to AUS: Conventional → DU or LP (client's choice or program eligibility); FHA → DU or LP (FHA accepts both); USDA → GUS; VA → DU (VA-approved lender with DU access)
3. Confirm all 1003 data is complete in LOS — AUS submission pulls from 1003 data
4. If both DU and LP are being run: submit to both; use more favorable findings

**LOS-to-AUS data mapping:**

The LOS MISMO XML export must correctly map 1003 data to AUS fields. Critical mappings to validate:

| 1003 Field | AUS Field | Common Mapping Error |
|-----------|-----------|---------------------|
| Borrower SSN | BorrowerSSN | Dashes stripped correctly |
| Property address (all components) | PropertyStreetAddress, City, State, ZIP | ZIP+4 if required |
| Loan amount | BaseLoanAmount | Must match LE; not purchase price |
| Property value / sales price | PropertyEstimatedValue (lower of appraised or sales) | Using purchase price before appraisal |
| Monthly income — all types | MonthlyIncome by income type | Bonus/overtime — 24-month average required |
| Monthly obligations | MonthlyLiability — each installment/revolving debt | Missing liabilities from credit report |
| Housing expense | HousingExpense (PI + taxes + insurance + HOA) | Escrow estimate must be included |
| Loan purpose | LoanPurposetype | Cash-out vs. rate-term distinction |
| Occupancy | PropertyUsageType | Investment property inputs differently |

---

## Section 3: Findings Interpretation

### 3a: DU Findings

**DU recommendation types:**

| DU Recommendation | Meaning | Workflow |
|------------------|---------|---------|
| Approve/Eligible | Loan meets Fannie Mae guidelines; DU has determined it is eligible for delivery | Proceed to processing using DU findings documentation requirements |
| Approve/Ineligible | DU approves the risk but loan is ineligible for delivery to Fannie for some reason (e.g., loan limit exceeded, property type) | Cannot deliver to Fannie; explore other options (Freddie, portfolio) |
| Refer | DU cannot approve; manual underwriting may be performed per Fannie guidelines | Manual UW required; more conservative documentation standards |
| Refer with Caution | DU has identified elevated risk factors; manual UW very unlikely to approve | Explore alternative programs or restructure |
| Out of Scope | Loan type not supported by DU (e.g., construction, reverse, HELOC) | Use appropriate AUS for loan type |

**DU Approve/Eligible documentation requirements (Documentation Type matrix):**

| Asset/Liability | DU Documentation Level | What to Collect |
|----------------|------------------------|----------------|
| Salaried income (stable employment 2 years) | Full documentation | 30-day pay stubs + W-2s (2 years) |
| W-2 only | W-2 waiver (DU may waive returns for W-2 employees) | Verify DU findings message for waiver |
| Self-employed | Full documentation — always | 2 years tax returns (personal + business) + YTD P&L |
| Bank accounts | Standard (2 months statements) | Most loans: 2 months most recent statements |
| Retirement accounts | If needed for reserves | 2 months or quarterly statement |
| Gift funds | Gift letter + donor bank statement | DU findings will specify if gift is acceptable |

**Reading DU findings for required verifications:**

The DU findings report lists specific verifications required. These override general Selling Guide requirements. Process:
1. Print or save DU findings report to loan file immediately upon receipt
2. Processor creates conditions checklist based on DU-listed verifications (not generic checklist)
3. If DU says "No income documentation required" — document this finding; do not require documentation anyway
4. If DU requires a verification not expected — research Selling Guide for explanation; do not override DU

### 3b: LP Findings

**LP feedback certificate types:**

| LP Recommendation | Meaning | Workflow |
|------------------|---------|---------|
| Accept | LP recommends the loan for purchase; reduced documentation applies | Use LP-specified documentation requirements |
| Caution | LP is unable to recommend; elevated risk; manual UW may be considered | LP Seller/Servicer Guide manual UW criteria apply |

**LP Accept documentation requirements:**

Similar to DU but with Freddie Mac-specific variations. Key differences from DU:
- LP uses the term "feedback certificate" for findings
- LP "ACE" (Automated Collateral Evaluation): if LP issues ACE, appraisal may be waived — verify in feedback certificate before ordering appraisal
- LP "LPA" verification messages differ in wording from DU — use Freddie Seller/Servicer Guide as reference
- For FHA loans run through LP: LP findings are for risk only; FHA program guidelines still apply for eligibility

**LP Accept — property eligibility notes:**

LP feedback certificate identifies property eligibility (e.g., condo project approval status, manufactured housing eligibility). If LP flags a proper