Key Takeaways

  • The Ability-to-Repay (ATR) rule requires lenders to verify eight factors including income, assets, debts, credit history, and DTI before making a loan
  • Qualified Mortgages (QM) provide legal safe harbor and must have points/fees <= 3% for loans >= $100,000, no negative amortization, term <= 30 years, and fully amortizing payments
  • Front-end DTI (housing ratio) compares housing expenses to gross income with a traditional benchmark of 28%, while back-end DTI includes all debts with benchmark of 36%
  • GSE QM loans allow DTI up to 45% (or 50% with strong compensating factors) while General QM uses a 43% DTI limit
  • Automated underwriting systems (DU and LPA) evaluate loan applications in seconds and provide conditional approvals with required documentation lists
  • Manual underwriting requires human review for loans that don't pass automated systems and applies stricter compensating factor requirements
Last updated: January 2026

Underwriting Guidelines

Mortgage underwriting determines whether a borrower qualifies for a loan. Understanding the Ability-to-Repay (ATR) rule and Qualified Mortgage (QM) standards is essential for MLO exam success.

Ability-to-Repay (ATR) Rule

The Ability-to-Repay rule requires lenders to make a reasonable, good-faith determination that a borrower can repay their mortgage. This rule was created by the Consumer Financial Protection Bureau (CFPB) under the Dodd-Frank Act.

Eight ATR Factors

Lenders must consider and verify at least eight factors:

#FactorWhat Lender Verifies
1Current income or assetsPay stubs, tax returns, bank statements
2Current employment statusVerification of employment (VOE)
3Monthly mortgage paymentCalculate P&I, taxes, insurance, HOA
4Monthly payments on other loansCredit report
5Monthly payment for mortgage-related obligationsProperty taxes, insurance, HOA
6Current debt obligationsCredit report, alimony, child support
7DTI ratio or residual incomeCalculate housing + all debts vs. income
8Credit historyCredit report, scores

ATR Applies To

  • All residential mortgage loans
  • Primary residence, second homes, investment properties
  • Purchase, refinance, and home equity loans

ATR Exemptions

Some loans are exempt from ATR requirements:

  • Reverse mortgages (HECMs)
  • Temporary or bridge loans (12 months or less)
  • Construction phase loans
  • Timeshare loans
  • Certain community development loans

Qualified Mortgages (QM)

A Qualified Mortgage is a category of loans that meet specific requirements and provide legal protection to lenders. QM loans are presumed to comply with ATR requirements.

QM Requirements

RequirementStandard
Points and Fees<= 3% of loan amount (for loans >= $100,000)
Loan Term30 years or less
Negative AmortizationNot permitted
Interest-OnlyNot permitted
Balloon PaymentsNot permitted (with limited exceptions)
Fully AmortizingRequired - must pay principal over loan term
VerificationIncome/assets must be verified

Points and Fees Thresholds

Loan AmountMaximum Points/Fees
>= $100,0003%
$60,000 - $99,999$3,000
$20,000 - $59,9995%
$12,500 - $19,999$1,000
< $12,5008%

Types of Qualified Mortgages

QM TypeDTI LimitDescription
GSE/Agency QMUp to 50%Loans eligible for Fannie/Freddie/FHA/VA/USDA
General QM43%Loans meeting General QM standards
Seasoned QMNone (performance-based)Loans held 36 months with no 60+ day delinquencies

Safe Harbor vs. Rebuttable Presumption

CategoryRate ThresholdLegal Protection
Safe Harbor QMAPR <= APOR + 1.5%Strong presumption of compliance
Rebuttable Presumption QMAPR > APOR + 1.5%Compliance can be challenged

APOR = Average Prime Offer Rate (published weekly by CFPB)


Debt-to-Income (DTI) Ratios

DTI ratios measure a borrower's monthly debt obligations compared to their gross monthly income.

Two Types of DTI

RatioAlso CalledFormula
Front-End DTIHousing ratioHousing expenses / Gross income
Back-End DTITotal DTIAll monthly debts / Gross income

Front-End (Housing) DTI

Includes:

  • Principal and interest (P&I)
  • Property taxes (T)
  • Homeowner's insurance (I)
  • HOA fees (if applicable)
  • Mortgage insurance (if applicable)

Traditional Benchmark: 28%

Back-End (Total) DTI

Includes everything in front-end PLUS:

  • Minimum credit card payments
  • Auto loan payments
  • Student loan payments
  • Personal loans
  • Child support/alimony
  • Other monthly obligations

Traditional Benchmark: 36%

DTI Limits by Program

Loan ProgramMaximum DTI
Conventional (with AUS approval)45-50%
FHA43% (up to 50% with compensating factors)
VANo maximum (residual income required)
General QM43%
GSE/Agency QMBased on AUS approval

DTI Calculation Example

Borrower's Monthly Finances:

  • Gross monthly income: $8,000
  • Proposed mortgage payment (PITI): $1,800
  • Car payment: $450
  • Student loans: $350
  • Credit cards (minimum): $200

Calculations:

  • Front-End DTI: $1,800 / $8,000 = 22.5%
  • Back-End DTI: ($1,800 + $450 + $350 + $200) / $8,000 = $2,800 / $8,000 = 35%

Automated Underwriting Systems (AUS)

Most loans are evaluated using automated underwriting systems before manual review.

Major AUS Platforms

SystemOwnerUsed For
Desktop Underwriter (DU)Fannie MaeConventional, FHA
Loan Product Advisor (LPA)Freddie MacConventional
GUSUSDAUSDA loans
VA LAPPVAVA loans

How AUS Works

  1. Data Entry: Loan officer inputs application data
  2. Analysis: System evaluates credit, income, assets, collateral
  3. Finding: System issues approval or referral
  4. Conditions: System generates required documentation list

AUS Findings

FindingMeaning
Approve/EligibleLoan meets guidelines, likely to close
Approve/IneligibleMay qualify with different product
Refer with CautionRequires manual underwriting
Out of ScopeCannot be evaluated by AUS

Benefits of AUS

  • Speed: Decisions in seconds vs. hours/days
  • Consistency: Same criteria applied uniformly
  • Documentation: Clear list of required items
  • Risk Assessment: Statistical analysis of default probability

Manual Underwriting

Manual underwriting occurs when a loan cannot be approved through AUS or lender policy requires human review.

When Manual Underwriting Required

  • AUS returns "Refer" finding
  • No credit score available
  • Loan doesn't fit AUS parameters
  • Lender overlay requires it

Manual Underwriting Requirements

Manual underwriting typically requires:

  • Lower DTI limits (36-45% vs. 50%)
  • More reserves (2-6 months PITI)
  • Stronger compensating factors
  • Additional documentation
  • More stringent credit review

Compensating Factors

Compensating factors are positive characteristics that offset weaknesses in an application.

Common Compensating Factors

FactorHow It Helps
Large down paymentReduces LTV, demonstrates financial capacity
Cash reservesProves ability to handle emergencies
Minimal DTI increasePayment similar to current housing
Strong credit historyDemonstrates payment reliability
Stable employmentLong tenure, consistent income
Residual incomeMoney left after paying all expenses
Cash-out reductionRefinancing to lower rate/payment

Using Compensating Factors

WeaknessPotential Compensating Factor
High DTILarge reserves, strong credit
Lower credit scoreLarge down payment, low DTI
Limited credit historyLarge reserves, stable employment
Self-employmentTwo+ years same business, strong reserves

Documentation Types

Documentation LevelDescription
Full DocumentationTax returns, pay stubs, W-2s, bank statements
Reduced DocumentationFewer documents, typically for strong files
Bank Statement12-24 months of bank statements for self-employed
Asset DepletionQualifies on assets rather than income

Non-QM Documentation

Non-QM loans may use alternative documentation:

  • Bank statements (12-24 months)
  • 1099 income only
  • Asset-based qualification
  • DSCR (debt service coverage ratio) for investors

Key Takeaways

  • The ATR rule requires verification of eight borrower factors
  • Qualified Mortgages must be fully amortizing with term <= 30 years
  • QM points/fees cannot exceed 3% for loans $100,000+
  • Front-end DTI = housing expenses only; back-end DTI = all debts
  • Traditional DTI benchmarks are 28%/36% but QM allows higher
  • AUS provides fast, consistent loan decisions
  • Compensating factors can offset application weaknesses
Loading diagram...
Ability-to-Repay Rule and Qualified Mortgage Relationship
Back-End DTI Limits by Standard (%)
Test Your Knowledge

Under the ATR rule, which of the following is NOT one of the eight factors lenders must consider and verify?

A
B
C
D
Test Your Knowledge

For a $400,000 Qualified Mortgage, what is the maximum amount of points and fees the lender can charge?

A
B
C
D
Test Your Knowledge

A borrower has gross monthly income of $10,000, a proposed mortgage payment (PITI) of $2,500, a car payment of $500, and student loans of $300. What is their back-end DTI ratio?

A
B
C
D