A teaser rate is a temporary introductory interest rate offered at the start of a loan or credit account. When the introductory period ends, the rate changes to the regular fixed rate or to a variable formula specified in the agreement, which can increase the payment or interest charge even if broader market rates do not rise.
Key Takeaways
- Teaser, introductory, start, and discounted rate can describe temporary initial pricing, but the contract’s terminology controls.
- The post-teaser rate, not the starting rate alone, determines later interest and payment risk.
- An adjustable-rate mortgage’s first reset may increase the rate even if its index is unchanged when the initial rate is below the fully indexed rate.
- A teaser rate is not the same as deferred interest, a temporary buydown, or a permanently subsidized rate.
- Total cost depends on the balance, fees, repayment schedule, caps, floors, and time the financing remains outstanding.
How a Teaser Rate Works
A teaser structure has at least two pricing periods:
- Introductory period: A stated rate applies for a defined number of billing cycles, months, or years.
- Post-introductory period: The regular rate or adjustment formula takes effect.
The agreement should identify:
- the introductory rate;
- the exact start and end dates;
- which balances or transactions qualify;
- the regular or fully indexed rate;
- the index, margin, and adjustment frequency for a variable rate;
- rate and payment caps or floors;
- fees and events that can end the promotion;
- how payments and balances are calculated.
An advertisement can emphasize the initial rate while the economically important transition appears in the detailed disclosures.
Teaser Rates in Adjustable-Rate Mortgages
An adjustable-rate mortgage may begin with a rate below the fully indexed rate. After the initial period, the basic reset calculation is:
$$
\text{Fully Indexed Rate}=\text{Index}+\text{Margin}
$$
The rate actually applied may be limited by an adjustment cap or floor. The payment can also depend on the remaining balance, remaining amortization term, payment caps, and whether unpaid interest has accumulated.
If the teaser rate is 3% while the fully indexed rate is already 4.5%, the first rate can rise to 4.5% when the teaser expires even if the index has not changed, subject to the agreement’s caps.
Worked Example: Mortgage Payment Reset
Assume an illustrative mortgage has:
- $300,000 initial principal;
- 30-year amortization;
- monthly principal-and-interest payments;
- 3% teaser rate for the first 12 months;
- 4.5% rate beginning after month 12;
- no fees, escrow, insurance, prepayments, caps, or negative amortization.
The initial monthly principal-and-interest payment is:
$$
M=\$300{,}000\frac{(0.03/12)(1+0.03/12)^{360}}{(1+0.03/12)^{360}-1}\approx\$1{,}264.81
$$
After 12 scheduled payments, the simplified remaining balance is approximately $293,736.60. Re-amortizing that balance over the remaining 348 months at 4.5% gives:
$$
M_{\text{reset}}\approx\$1{,}512.72
$$
The principal-and-interest payment increases by about $247.91 per month, or 19.6%, under these assumptions. Taxes, insurance, escrow, payment dates, rounding, caps, and the actual index value can produce a different result.
The example shows why the percentage-point change and the payment change are not the same measure.
Teaser Rate Compared with Similar Offers
| Structure | What happens initially | What happens later | Main distinction |
|---|
| Teaser or introductory rate | Temporary below-regular rate applies | Regular fixed or variable pricing begins | Interest is charged at the introductory rate during the initial period |
| Hybrid ARM initial fixed rate | Rate is fixed for an initial term | Rate resets periodically | Initial rate is not necessarily discounted below the fully indexed rate |
| Temporary mortgage buydown | Payments may be reduced using subsidy funds | Scheduled payment increases as subsidy ends | Note rate may differ from the rate used to describe early payments |
| Zero-percent promotion | No interest accrues on qualifying balance during stated period | Regular rate applies to remaining balance prospectively | True 0% is not retroactive deferred interest |
| Deferred interest | Interest may accrue but is conditionally waived | Accrued interest can become payable if conditions are not met | “No interest if paid in full” is not the same as 0% APR |
Marketing labels vary. Verify the legal and disclosure terms rather than classifying a product from one phrase.
Credit-Card Introductory Rates
A card issuer may offer a temporary purchase or balance-transfer APR. Important details include:
- which transaction type receives the promotional rate;
- whether a transfer fee applies;
- the promotion’s expiration date;
- the APR after expiration;
- minimum-payment and payment-allocation rules;
- whether new purchases have a grace period;
- events that can affect promotional eligibility.
A 0% balance-transfer rate with an upfront transfer fee is not costless. A purchase promotion may also interact with other card balances carrying different APRs.
Why Payment Shock Can Occur
Payment shock is a material increase in required payment after the introductory period. It can arise from:
- a higher post-teaser interest rate;
- re-amortization over a shorter remaining term;
- payment caps that previously delayed full adjustment;
- transition from interest-only to amortizing payments;
- accumulated unpaid interest;
- simultaneous escrow or fee changes.
Rate caps can limit specified interest-rate changes but may not prevent all payment increases.
How to Evaluate a Teaser Rate
- Record the introductory rate and exact expiration date.
- Identify the post-teaser rate or formula.
- Calculate the fully indexed rate using the current index and stated margin.
- Apply initial, periodic, and lifetime caps in the correct order.
- Determine when the payment is recalculated and over what remaining term.
- Include points, origination charges, transfer fees, and other costs.
- Check whether the promotion applies to every balance or only selected transactions.
- Model payments at the first reset and at the maximum rate allowed by the agreement.
- Avoid assuming that refinancing, sale, or balance transfer will be available before expiration.
- Use the agreement, required disclosures, and account statements as the controlling evidence.
Common Mistakes
- Comparing only the initial payment.
- Assuming the first reset requires a market-rate increase.
- Treating a hybrid ARM’s initial fixed period as a full-term fixed rate.
- Confusing a temporary buydown with a reduced note rate.
- Assuming a true 0% promotion and deferred interest are equivalent.
- Ignoring fees and promotional balance restrictions.
- Assuming the payment changes on the same date or by the same percentage as the rate.
- Planning on a future refinance without considering eligibility, property value, fees, or market conditions.
Risks and Limitations
A teaser rate lowers initial interest or payments but can shift cost and uncertainty into later periods. Post-promotion rates, payment shock, negative amortization, fees, changing benchmarks, and limited refinancing options can affect affordability. A lower initial rate does not prove lower total cost or suitability.
This page provides general financial education, not individualized borrowing, mortgage, legal, tax, or investment advice.
Public Verification Sources
FAQs
Can a teaser rate rise even if its index does not change?
Yes. If the initial rate is below the fully indexed rate, expiration can cause an increase even with an unchanged index, subject to the loan’s caps and formula.
Is every initial ARM rate a teaser rate?
No. An ARM may have an initial fixed period without the initial rate being discounted below the fully indexed rate.
Is a teaser rate the same as deferred interest?
No. A teaser rate charges interest at a temporary rate. Deferred interest may accrue at another rate and become payable if the promotional conditions are not met.
Does an interest-rate cap prevent payment shock?
Not necessarily. Caps limit defined rate changes, but payment recasting, ending interest-only terms, accumulated interest, fees, or escrow changes can still increase payments.