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Financing exam concept

Fixed-rate vs. adjustable-rate mortgage

Fixed means the contract rate stays put. Adjustable means a formula can reset it. For an ARM, identify the initial period, adjustment frequency, index, margin, caps, floor, and maximum payment exposure before deciding what happens. The memorized formula is index plus margin, but the tested answer often turns on a cap that prevents the calculated rate from taking effect all at once.

Last updated: August 1, 2026

What is the difference at a glance?

Short answer: A fixed-rate mortgage keeps the note rate constant, which ordinarily stabilizes scheduled principal and interest on a fully amortizing loan. An ARM can hold an initial rate for a stated period and then reset on scheduled dates. The preliminary reset calculation is index plus margin. Apply the initial adjustment cap at the first reset, the periodic cap at later resets, the lifetime cap to the total permitted increase, and any floor to decreases. Then calculate the payment from the adjusted rate, current balance, and remaining amortization period. Taxes, insurance, mortgage insurance, and escrow can change even when the note rate is fixed.

Official section
National IV.B: Types of Loans
Broker weight
Part of 10% of the national portion
Expected scored items
The current PSI broker outline assigns about 10 of 100 scored national items to Financing

ARM provisions are document-specific. Product notation, index observation, lookback period, rounding, caps, floors, carryover, payment recast, interest-only period, and replacement-index rules can differ. Current conventional uniform instruments use 30-day Average SOFR for certain ARM products, but older loans and other programs can use other indices. Use the stem's facts for exam calculations and the executed note and disclosures for a real loan. Sources cited here were checked through August 1, 2026.

What changes from one term to the next?

Terms
Fixed-rate mortgage vs. ARM
Difference
A fixed-rate mortgage keeps its contract rate unchanged. An ARM permits rate changes under a stated index, margin, timing, and cap formula.
Question cue
Rate certainty versus formula-based resets.
Terms
Index vs. margin
Difference
The index is the variable market benchmark. The margin is the lender-set contractual number of percentage points added to it.
Question cue
Moving benchmark versus fixed add-on.
Terms
Fully indexed rate vs. effective rate
Difference
The fully indexed rate is index plus margin. The effective reset rate is what remains after caps, floors, and rounding apply.
Question cue
Formula result versus permitted charged rate.
Terms
Initial rate vs. fully indexed rate
Difference
The initial rate applies at closing and may be discounted or otherwise different. The fully indexed rate uses the current index plus margin.
Question cue
Starting offer versus formula rate.
Terms
Initial cap vs. periodic cap
Difference
The initial cap governs the first reset after the fixed period. The periodic cap governs each later adjustment from the previous rate.
Question cue
First change versus later changes.
Terms
Periodic cap vs. lifetime cap
Difference
The periodic cap limits one reset. The lifetime cap limits the total permitted increase over the full loan.
Question cue
One step versus overall ceiling.
Terms
Rate cap vs. floor
Difference
A cap limits upward or interval movement as stated. A floor sets the lowest permitted rate.
Question cue
Upper-change protection versus minimum rate.
Terms
Rate cap vs. payment cap
Difference
A rate cap limits the interest rate change. A payment cap limits payment movement and can permit unpaid interest if the rate cost exceeds the payment.
Question cue
Interest limit versus cash-payment limit.
Terms
Note rate vs. APR
Difference
The note rate calculates contractual interest. APR is a standardized disclosure measure of credit cost using specified fees and assumptions.
Question cue
Interest calculation versus comparison disclosure.
Terms
Principal-and-interest stability vs. total-payment stability
Difference
A fixed fully amortizing loan can stabilize principal and interest. Taxes, insurance, mortgage insurance, and escrow can still alter the total payment.
Question cue
Loan component versus full housing bill.

How does the distinction change the answer?

Fully indexed rate without a binding cap

Scenario: At an adjustment, the stated index is 3.80% and the contractual margin is 2.25%. The note's caps do not restrict this reset.

  1. Add the index and margin.
  2. 3.80% plus 2.25% equals 6.05%.
  3. No cap or floor changes the formula result on the facts.

Answer: The new rate is 6.05%, subject to the note's rounding convention if one is stated.

Initial cap controls

Scenario: An ARM begins at 4.00%. At the first reset, index plus margin equals 7.25%, but the initial adjustment cap allows an increase of no more than 2 percentage points.

  1. The fully indexed rate is 7.25%.
  2. The first-reset ceiling is 4.00% plus 2.00%, or 6.00%.
  3. The initial cap prevents the entire formula rate from applying now.

Answer: The permitted first-reset rate is 6.00%.

Periodic cap controls

Scenario: The prior effective ARM rate is 6.00%. At the next annual reset, index plus margin equals 8.40%, and the periodic cap is 1 percentage point.

  1. The formula produces 8.40%.
  2. The periodic cap permits only 1 percentage point above the prior 6.00% rate.
  3. Any lifetime ceiling is assumed not to be lower in this example.

Answer: The new effective rate is capped at 7.00% for this adjustment.

Lifetime cap controls

Scenario: An ARM began at 3.50% and has a 5-percentage-point lifetime increase cap. At a later reset, other caps would permit 9.00%.

  1. The lifetime ceiling is 3.50% plus 5.00%.
  2. That produces a maximum rate of 8.50%.
  3. The lifetime limit overrides the otherwise permitted 9.00% result.

Answer: The rate cannot exceed 8.50% under the stated lifetime cap.

Index falls but a floor applies

Scenario: The index falls to 0.75%, the margin is 2.25%, and the loan has a 3.50% minimum rate.

  1. Index plus margin equals 3.00%.
  2. The floor prevents a rate below 3.50%.
  3. A falling index therefore does not deliver the full calculated decrease.

Answer: The effective rate is 3.50% under the stated floor.

Fixed rate but changing total payment

Scenario: A homeowner's fixed-rate principal-and-interest payment is unchanged, but the servicer increases the escrow deposit after property taxes and insurance premiums rise.

  1. The note rate has not adjusted.
  2. Principal and interest remain fixed on the stated schedule.
  3. Escrowed property costs are separate components of the total payment.

Answer: The total payment can rise without converting the loan into an ARM.

The A-D-J-U-S-T ARM test

  1. At closing: record the initial rate, initial principal-and-interest payment, loan term, amortization, and fixed-period end date.
  2. Date: identify the first adjustment, later adjustment frequency, index observation, lookback period, and notice timing.
  3. Join: add the current index and contractual margin to find the preliminary fully indexed rate.
  4. Upper and lower limits: apply initial, periodic, and lifetime caps, the floor, and any rounding rule.
  5. Set payment: use the permitted rate, current balance, remaining term, and any interest-only or payment-cap provision.
  6. Test exposure: compare minimum, expected, and maximum payments with income, reserves, holding period, sale, and refinance risk.
Feature
Contract rate
Fixed-rate mortgage
Unchanged
ARM
Can reset
Exam check
Read note terms
Feature
Formula
Fixed-rate mortgage
Set at closing
ARM
Index plus margin
Exam check
Then apply caps and floor
Feature
Principal and interest
Fixed-rate mortgage
Usually level if fully amortizing
ARM
Can recalculate
Exam check
Use current balance and remaining term
Feature
Total payment
Fixed-rate mortgage
Can change
ARM
Can change
Exam check
Taxes and insurance remain variable

Where do similar terms create traps?

Trap
Saying fixed rate means fixed total payment
Correction
Taxes, insurance, mortgage insurance, and escrow requirements can change even when principal and interest do not.
Trap
Using index alone as the ARM rate
Correction
Add the contractual margin before applying caps, floor, and rounding.
Trap
Treating margin as the moving component
Correction
The margin is ordinarily fixed by the note; the index reflects market movement.
Trap
Stopping after index plus margin
Correction
Test the formula result against the applicable initial, periodic, and lifetime limits.
Trap
Applying the periodic cap at the first reset
Correction
Use the initial adjustment cap for the first change when the note provides separate limits.
Trap
Measuring every cap from the initial rate
Correction
A periodic cap commonly measures from the prior effective rate; the lifetime ceiling commonly measures total change from the initial rate.
Trap
Assuming a falling index guarantees a lower rate
Correction
The margin, floor, caps, rounding, and prior-rate rule can limit or prevent the decrease.
Trap
Confusing rate cap and payment cap
Correction
A capped payment can be too small to cover interest and can create deferred interest under some products.
Trap
Treating 5/1 as a five-year loan
Correction
The five generally describes the initial fixed-rate period, not the full mortgage term.
Trap
Assuming all ARMs adjust annually
Correction
Read the note because current products can use annual, six-month, or other stated schedules.
Trap
Confusing note rate and APR
Correction
Use the note rate for interest calculations and APR as a broader disclosure measure.
Trap
Recommending a loan from the initial rate alone
Correction
Compare margin, caps, floor, fees, maximum payment, holding period, and refinance or sale risk.

Can you separate the terms in a new fact pattern?

These questions are original study items aligned to the published outline. They are not copied, recalled, or predicted PSI questions.

1. Which mortgage keeps its contract interest rate unchanged for the loan term?

  1. Fixed-rate mortgage
  2. Adjustable-rate mortgage
  3. Shared-appreciation mortgage
  4. Open-end mortgage
Show answer and explanation

Answer: Fixed-rate mortgage

The defining feature is rate certainty, though taxes and insurance can still change the total payment.

2. An ARM index is 4.10% and its margin is 2.25%. Before caps and rounding, what is the fully indexed rate?

  1. 6.35%
  2. 4.10%
  3. 2.25%
  4. 1.85%
Show answer and explanation

Answer: 6.35%

Index plus margin equals 4.10% plus 2.25%, or 6.35%.

3. Which cap limits the first rate change after a hybrid ARM's initial fixed period?

  1. Initial adjustment cap
  2. Subsequent adjustment cap
  3. Loan-to-value cap
  4. Escrow cap
Show answer and explanation

Answer: Initial adjustment cap

The initial adjustment cap applies at the first reset; later changes use the subsequent or periodic cap.

4. An ARM began at 4.00% with a 5-percentage-point lifetime cap. What is its stated lifetime ceiling?

  1. 9.00%
  2. 5.00%
  3. 4.00%
  4. 20.00%
Show answer and explanation

Answer: 9.00%

The maximum total increase is added to the initial rate: 4.00% plus 5.00% equals 9.00%.

5. A homeowner's fixed-rate loan payment rises only because annual property taxes increased. Which statement is best?

  1. The loan can remain fixed rate because escrow changed
  2. The loan automatically became an ARM
  3. The note rate must have increased
  4. Property taxes are principal
Show answer and explanation

Answer: The loan can remain fixed rate because escrow changed

Fixed rate refers to the contract interest rate. Escrowed taxes and insurance are separate total-payment components.

Where do these ideas appear on the outline?

Topic
Fixed-rate mortgage
What to know
Constant note rate, full term, principal and interest, level payment, amortization, rate certainty, market-rate movement, refinance, prepayment, taxes, insurance, escrow, and no total-payment guarantee
Best exam move
Choose fixed rate when the interest rate itself cannot change under the original loan terms.
Topic
Adjustable-rate mortgage
What to know
Variable rate, initial period, reset, index, margin, fully indexed rate, adjustment date, caps, floor, rounding, payment recast, notice, and future-rate risk
Best exam move
Choose ARM when the note uses a formula and schedule that permit the rate to change after closing.
Topic
Initial rate
What to know
Start rate, introductory rate, teaser rate, premium rate, fixed period, temporary rate, discount, note rate, first payment, first adjustment, and no fully indexed assumption
Best exam move
Do not assume the initial rate equals index plus margin; calculate the fully indexed rate separately.
Topic
Initial fixed period
What to know
Three years, five years, seven years, ten years, hybrid ARM, first reset date, payment certainty, product notation, month count, year count, and no loan-term confusion
Best exam move
The first number in common hybrid-ARM notation usually identifies how long the initial rate remains fixed.
Topic
Adjustment frequency
What to know
Annual, semiannual, six month, monthly, first adjustment, later adjustment, reset date, rate-change notice, product notation, lookback, and calendar schedule
Best exam move
Identify how often the rate can change after the initial period rather than how often payments are made.
Topic
Index
What to know
Market benchmark, 30-day Average SOFR, Treasury-based index, published source, observation date, lookback, replacement index, movement, not borrower credit, not lender margin, and verification
Best exam move
Treat the index as the variable market component named in the note.
Topic
Margin
What to know
Lender-set percentage points, contract term, fixed after closing, added to index, pricing, fully indexed rate, comparison, no market-index movement, and note disclosure
Best exam move
Add the stated margin to the index before testing caps, floors, and rounding.
Topic
Fully indexed rate
What to know
Index plus margin, preliminary reset, calculated rate, note formula, caps, floor, rounding, initial-rate difference, payment, and no automatic actual-rate conclusion
Best exam move
Calculate index plus margin, then determine whether the note permits that entire rate at the current adjustment.
Topic
Initial adjustment cap
What to know
First rate change, end of fixed period, increase limit, decrease limit, initial note rate, percentage points, cap structure, hybrid ARM, and no periodic-cap substitution
Best exam move
Apply the initial cap only to the first reset and measure it from the rate specified by the note.
Topic
Subsequent adjustment cap
What to know
Periodic cap, later reset, previous rate, increase limit, decrease limit, annual reset, semiannual reset, rate carryover, and repeated changes
Best exam move
At a later reset, compare the new calculated rate with the prior effective rate and apply the periodic cap.
Topic
Lifetime cap
What to know
Maximum total increase, initial rate, ceiling, loan life, minimum rate, floor, product cap numbers, worst-case rate, earliest maximum date, and affordability
Best exam move
The effective rate cannot exceed the contractual lifetime ceiling even if index plus margin is higher.
Topic
Floor
What to know
Minimum rate, margin floor, initial-rate floor, lifetime decrease limit, index decline, downward cap, note terms, no guaranteed decrease, and rounding
Best exam move
If the index falls, test the calculated rate against the note's minimum-rate rule.
Topic
Rate cap versus payment cap
What to know
Interest-rate limit, payment-change limit, deferred interest, negative amortization, recast, balance cap, periodic payment, fully amortizing payment, and separate provisions
Best exam move
A payment cap does not necessarily cap accrued interest; unpaid interest can increase principal if the documents allow it.
Topic
Payment recalculation
What to know
Adjusted rate, current principal, remaining term, amortization, principal and interest, monthly payment, interest-only feature, recast, scheduled change, and escrow exclusion
Best exam move
After finding the permitted new rate, use the current balance and remaining amortization period for a standard payment recast.
Topic
Total monthly payment
What to know
Principal, interest, property taxes, homeowners insurance, mortgage insurance, escrow, dues, assessments, fixed rate, ARM, changing non-rate items, and affordability
Best exam move
Fixed rate stabilizes the note rate, not every component of the borrower's housing payment.
Topic
ARM disclosures
What to know
Loan Estimate, Adjustable Interest Rate table, AIR table, index plus margin, initial rate, minimum, maximum, first change, frequency, limits, projected payments, CHARM booklet, Closing Disclosure, and note
Best exam move
Use the AIR table and projected payments to identify how and when the rate and payment can change.
Topic
Borrower risk comparison
What to know
Payment certainty, initial rate, holding period, rate increase, rate decrease, sale, refinance, qualification, income stability, cash reserve, worst-case payment, points, fees, and break-even
Best exam move
Compare total terms and maximum affordable exposure rather than declaring one product universally superior.
Topic
Broker boundaries
What to know
General explanation, no rate quote, no suitability promise, no refinance guarantee, lender, loan originator, CHARM booklet, disclosure review, affordability, current index, and executed note
Best exam move
Explain vocabulary and direct loan selection, pricing, qualification, and disclosure questions to licensed mortgage professionals.

How do you make the distinction stick?

Session
Session 1
Focus
Separate fixed and adjustable
Proof you are ready
Classify 20 product descriptions by rate behavior, payment behavior, and non-loan payment changes.
Session
Session 2
Focus
Master index and margin
Proof you are ready
Calculate 20 fully indexed rates and explain why each is preliminary rather than automatically effective.
Session
Session 3
Focus
Apply all three caps
Proof you are ready
Solve first-reset, later-reset, and lifetime-ceiling problems with changing indices and prior rates.
Session
Session 4
Focus
Read timing and product notation
Proof you are ready
Map initial period, first change, subsequent frequency, index lookback, and notice for 10 sample ARM structures.
Session
Session 5
Focus
Audit disclosures and risk
Proof you are ready
Locate the AIR table, minimum and maximum rate, projected payments, points, APR, and worst-case payment in sample forms.
Session
Session 6
Focus
Run the A-D-J-U-S-T test
Proof you are ready
Score at least 90% and state closing rate, date, joined rate, limits, payment, and exposure for every miss.

Do not count recognition as mastery. Close the notes and explain the rule, apply it to a new fact pattern, and identify why each distractor fails.

Turn the comparison into a test-day decision

From concept to decision

Drill this topic, then review the explanation

Pass Illinois gives you original national and Illinois questions, topic-by-topic study, clear explanations, timed practice, flashcards, progress tracking, and Math Coach. Start free, find the weak distinction, and focus the next session there.

Questions students ask about Fixed-Rate vs. Adjustable-Rate Mortgage

What is a fixed-rate mortgage?

A fixed-rate mortgage keeps its contract interest rate unchanged for the loan term. On a typical fully amortizing loan, the scheduled principal-and-interest payment also remains level. The borrower's total payment can still change if property taxes, homeowners insurance, mortgage insurance, escrow requirements, or other charges change.

What is an adjustable-rate mortgage?

An adjustable-rate mortgage, or ARM, allows the interest rate to change at stated times under a contractual formula. After any initial fixed period, the creditor generally combines a specified index with a fixed margin and applies the loan's rate caps, floor, lookback, rounding, and other terms.

What is the ARM index?

The index is the market-based benchmark named in the loan documents. It can move up or down with market conditions and is outside the borrower's personal control. The exact source, observation date, lookback, and replacement-index provisions matter. Current uniform instruments include products based on 30-day Average SOFR, but candidates should use the index stated in the question.

What is the ARM margin?

The margin is the number of percentage points the lender adds to the index to calculate the fully indexed rate. It is established in the loan agreement and ordinarily does not change after closing. Index plus margin produces the calculated rate before contractual caps, floors, and rounding are applied.

What is a fully indexed rate?

The fully indexed rate is the index plus the margin. If the index is 4.20% and the margin is 2.25%, the fully indexed rate is 6.45%. The rate actually charged at an adjustment can differ because an initial, periodic, or lifetime cap, a floor, or the note's rounding rule applies.

What are the three main ARM rate caps?

The initial adjustment cap limits the first change after the fixed period. The subsequent or periodic cap limits later changes from one adjustment to the next. The lifetime cap limits the total increase over the loan's life, usually measured from the initial rate under the note. A floor can limit downward movement.

What does a 5/1 ARM mean?

In the common 5/1 notation, the rate is fixed for the first five years and can adjust once each year afterward. Current products can use different adjustment frequencies, including six-month schedules, so always read the product name, Adjustable Interest Rate table, and note rather than assuming the second number uses the same unit in every document.

Can an ARM rate decrease?

It can if the index falls and the note permits a lower rate, but the margin, floor, caps, rounding, and prior-rate limits can prevent the borrower from receiving the entire market decline. Never state that an ARM payment must fall merely because a benchmark moved down.

Is APR the same as an ARM interest rate?

No. The note rate is used to calculate interest under the loan terms. APR is a disclosure measure designed to reflect the annualized cost of credit, including specified charges and assumptions. Compare note rate, APR, points, fees, payment features, and maximum exposure separately.

Are these official PSI questions?

No. They are original questions aligned to the national Financing outline effective June 24, 2026. The current PSI bulletin, CFPB mortgage guidance and CHARM booklet, Regulation Z, and current Fannie Mae and Freddie Mac uniform instruments were reviewed through August 1, 2026.

Primary sources

The current official outline controls the tested scope. Statutes, regulations, and official agency materials control when a general study rule and a jurisdiction-specific rule differ.

Editorial status

Checked against primary sources

The Pass Illinois editorial team last checked this guide on August 1, 2026. Every practice question is an original study item, and the source links above let you verify the rules that support the lesson.

Read our editorial and corrections process

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