What a 1% Move in Prime Does to a $500K SBA Loan Payment
The WSJ Prime Rate just dropped to 6.75%, a three-year low. Because most SBA loans are variable-rate, one point of Prime isn't abstract: on a $500,000 loan at Prime + 2 over 10 years, here's exactly what a 1% move does to your payment, in both directions, and why you feel it on the loan you already have.
The WSJ Prime Rate just dropped to 6.75% — its lowest level in three years. If you have (or are about to take) an SBA 7(a) loan, that number matters more than most headlines, because of a detail people forget: most SBA loans are variable-rate.
What “variable” actually means here
An SBA 7(a) loan is almost always priced as Prime plus a fixed spread — for a well-qualified borrower, right around Prime + 2. The spread is locked for the life of the loan. Prime is not. Your note spells out an adjustment schedule (usually monthly or quarterly), and each time Prime moves, the lender recalculates your rate and re-sizes the payment to keep the same payoff date.
The practical upshot: when Prime falls, the payment on the loan you already have drops automatically — no refinance, no paperwork. When Prime rises, it climbs the same way. So a change in Prime isn’t only a “new loans” story — it flows straight through to the balance you’re carrying right now.
What one point is worth on a $500K loan
Take a common file: a $500,000 SBA loan at Prime + 2 on a 10-year (120-month) term. At today’s Prime of 6.75%, that’s a rate of 8.75%. Here’s what a 1% move in Prime does — in both directions:
| Prime | Your rate (+2) | Monthly payment | Vs. today |
|---|---|---|---|
| 5.75% — down 1% | 7.75% | $6,001 | −$266 / mo |
| 6.75% — today | 8.75% | $6,267 | — |
| 7.75% — up 1% | 9.75% | $6,539 | +$272 / mo |
So one point of Prime is worth roughly $266–$272 a month on this loan — about $3,200 a year, and more than $31,000 in total interest over the full 10-year term. That swing runs in both directions, and because the loan is variable, it happens on its own.
Why it’s bigger than the monthly number
- It compounds over the whole term. Under $300 a month doesn’t sound dramatic, but across 120 months a single point is more than $31,000 — money that either stays in the business or leaves it.
- It changes what you qualify for. Lenders size SBA loans off debt-service coverage, so a lower payment means the same cash flow supports a bigger loan. A 1% drop can be the difference between a decline and an approval — or between $450K and $500K.
- You feel it without lifting a finger. On a variable loan, a Prime cut is an automatic raise for your cash flow and a Prime hike is an automatic cost — worth knowing which way things are moving before you lock in a loan amount.
The honest read today: Prime sits at a three-year low, which puts the math in your favor right now — on new loans and on the payment of any variable SBA loan you already carry. Whether it holds is anyone’s guess, which is the real argument for acting while pricing is good instead of trying to call the exact bottom.
Want the number on your own loan amount and rate? Run it through our calculator, or take the 60-second prequal and we’ll tell you where you actually land.
Figures are illustrative, using standard amortization on a $500,000 balance at Prime + 2 over 120 months; your actual rate, spread, and adjustment schedule depend on your credit profile and lender. For where SBA pricing is landing right now, see our note on Prime falling below 7%.
