Fixed versus variable rate on a business term loan, and what a reset actually does to the payment

A variable-rate loan is priced as an index plus a margin. The index moves with the market. The margin is set at underwriting and normally does not move. If the index is the prime rate and your margin is 2.5 points, your rate is prime plus 2.5, recalculated whenever the contract says to recalculate.

Everything that matters about a variable rate lives in the four terms below, and none of them is the rate itself.

Illustrative only — what a two-point reset does

Illustrative only — assume $250,000 drawn, a 120-month amortisation schedule, an opening rate of 8.5% per year charged monthly, and a single reset at the end of month 24 to a new rate that then holds. These are chosen inputs, not a forecast and not a market range.

At 8.5% the payment is $3,099.64. After 24 payments the balance is $215,370.66.

If the loan recasts the payment over the remaining 96 months:

• Reset to 9.5%: new payment $3,211.37 (up $111.73)
• Reset to 10.5%: new payment $3,325.33 (up $225.68, or 7.3%)
• Reset to 11.5%: new payment $3,441.49 (up $341.85)
• Reset to 12.5%: new payment $3,559.82 (up $460.18)

Two points on the rate moved the payment by 7.3%, not by 24%. That surprises people. The reason is that most of the payment is principal repayment, which the rate does not touch, and the amortisation window has already shortened from 120 months to 96.

The other kind of reset: same payment, longer term

Some agreements hold the payment constant and extend the term instead. Using the same figures, if the rate resets to 10.5% at month 24 and the payment stays at $3,099.64, the loan takes about 107.5 months to clear instead of 96 — roughly a year longer, and about a year more interest.

That structure protects this month's cash flow and quietly costs you more. It is not worse in every case. If a payment increase would breach a covenant or break payroll, term extension may be exactly what you want. Just do not mistake it for the rate change being smaller.

There is a third variant to watch for: a payment that does not change and a term that cannot extend, which forces the shortfall into a balloon at maturity. That combination can be survivable or brutal depending on the size of the balloon, so find out at signing what the maturity balance would be under a range of rate paths.

What to check in the rate clause

1. Caps. Is there a periodic cap (how much the rate can move at one reset) and a lifetime cap (the ceiling over the whole loan)? A loan with no lifetime cap has no defined worst case.
2. Floors. Many commercial agreements set a floor on the index or on the all-in rate. A floor means your rate can rise with the market but may not fall with it below a stated level.
3. The pricing grid. Some agreements tie the margin to a covenant such as a debt-to-EBITDA or coverage test. Miss the test and the margin steps up. That is a rate increase caused by your own results, not by the market, and it arrives at the worst possible moment.
4. Default rate. Almost every note carries a higher rate that applies after an event of default. Read what triggers it and how long the cure period is. See default rate and cure period.
5. Conversion rights. Some variable loans allow a one-time conversion to a fixed rate, sometimes at a fee. Whether that option exists is worth knowing before you need it.

Choosing between them

Fixed is worth paying for when the payment is tight relative to your cash flow, when the loan is long, or when you cannot easily raise prices if costs rise. Certainty has a price, and if a breach of covenant or a missed payroll is the failure mode, certainty is cheap.

Variable is defensible when the loan is short, when you expect to repay early and the prepayment terms allow it, or when the margin offered on the variable version is meaningfully tighter than the fixed alternative and you have the cash buffer to absorb resets.

What underwriting generally looks at is whether you can service the loan under a stressed rate, not just the opening rate. Many credit policies model a rate shock for exactly this reason. Policy varies by institution, and some lenders show you the stressed payment they used if you ask. Run the same test yourself before you sign: take the opening payment, add two or three points to the rate, recast over the remaining term, and see whether the business still clears its coverage test. If it does not, you have learned something about the loan and about the business.