Prime Rate vs. SOFR: How Benchmarks Affect Your Business Loan

Most business loans don't have a fixed rate that stays constant for the full term. They have a variable rate — usually expressed as a benchmark rate plus a spread. When the benchmark moves, your rate moves with it.

Understanding which benchmark rate your loan uses, how that rate is set, and what a rate change means for your payment is essential for any borrower with variable-rate debt.

The Prime Rate

The Prime Rate is the interest rate that major U.S. banks charge their most creditworthy customers. In practice, it's not individually set by each bank — it's published by the Wall Street Journal as a consensus rate and moves with the Federal Funds Rate.

How Prime is set:

• The Federal Reserve's Federal Open Market Committee (FOMC) sets the Federal Funds Rate at meetings throughout the year
• The Prime Rate moves in lockstep: traditionally, Prime = the top of the Fed's federal funds target range + 3%
• When the Fed raises rates by 0.25%, Prime rises by 0.25%
• When the Fed cuts rates by 0.50%, Prime falls by 0.50%

As of September 2026, Prime was 7%.

How Prime affects your loan:

Most variable-rate small business loans are priced as Prime + a spread. The spread reflects the lender's risk assessment of the borrower — lower spread for stronger borrowers, higher spread for weaker ones.

Example: "Prime + 2.25%" on a loan originated when Prime was 8.5% (its level from July 2023 to September 2024) = 10.75% total rate. If Prime drops to 7.5%, your rate drops to 9.75%. Your monthly payment changes accordingly.

Products commonly tied to Prime:

• SBA 7(a) loans (variable-rate option)
• Business lines of credit from banks
• Some commercial real estate loans
• Equipment financing with variable terms

SOFR (Secured Overnight Financing Rate)

SOFR replaced LIBOR (London Interbank Offered Rate) as the primary benchmark for institutional and commercial lending. LIBOR was phased out in 2023 following a rate-manipulation scandal. SOFR is now the dominant benchmark for larger commercial transactions and many adjustable-rate products.

What SOFR is: SOFR is a measure of the cost of borrowing cash overnight collateralized by U.S. Treasury securities. It's calculated and published daily by the Federal Reserve Bank of New York, based on actual transactions — not estimates, which was one of LIBOR's vulnerabilities. As of September 2026, SOFR was 3.88%.

How SOFR differs from Prime:

• SOFR is a backward-looking rate (based on yesterday's transactions). Prime changes only when the Fed changes its target range, usually the next day.
• SOFR can be more volatile day-to-day than Prime
• SOFR is primarily used in institutional and commercial real estate lending; Prime is more common in small business lending
• SOFR-based loans often use term SOFR (30-day, 90-day, 180-day averages) to smooth daily volatility

Products commonly tied to SOFR:

• Larger commercial real estate loans from institutional lenders
• Fannie Mae and Freddie Mac multifamily adjustable-rate mortgages
• CMBS floating-rate loans
• SBA 7(a) loans, when the lender chooses it: since March 1, 2026, SBA lets 7(a) lenders use SOFR or the 5- or 10-year Treasury as the base rate instead of Prime (the maximum rate is still set off Prime)

The Spread: What's Above the Benchmark

Your actual interest rate = Benchmark + Spread. The spread is what the lender charges above the benchmark, reflecting:

• Your creditworthiness (lower credit score = higher spread)
• Loan type and collateral (unsecured = higher spread than secured)
• Loan term (longer term = often higher spread)
• Market conditions and lender competition

The spread is fixed at loan origination and doesn't change with market conditions. The benchmark moves; the spread doesn't.

Typical spreads as of September 2026: SBA 7(a) Prime + 1.5–4.5%, bank business lines of credit Prime + 1.75–4%, bank term loans Prime + 0.5–4%, and bank construction loans SOFR + 2.75–4%. See current commercial real estate loan rates for how each program is priced.

How Rate Changes Affect Your Payment

Every 0.25% change in the benchmark rate changes your payment. How much depends on your loan balance and term.

Approximate payment impact per 0.25% rate change, for a fully amortizing loan starting at 9.25% (Prime of 7% + 2.25%):

• $100,000 loan, 5-year term: ~$12/month per 0.25% change
• $500,000 loan, 10-year term: ~$68/month per 0.25% change
• $1,000,000 loan, 25-year term: ~$173/month per 0.25% change

Longer terms feel each move more, because more of the payment is interest. Run your own numbers with the SBA 7(a) loan calculator.

For a business line of credit where you're drawing and repaying regularly, the rate change affects only the outstanding balance.

Rate Caps on Variable Loans

Some variable-rate loans include caps that limit how high the rate can go, regardless of benchmark movement. Common cap structures:

• Periodic cap: Limits how much the rate can change in any single adjustment period
• Lifetime cap: Maximum rate over the life of the loan

SBA 7(a) variable-rate loans have a regulatory cap on the spread, not on the rate itself: for loans over $350,000 the rate can be no more than Prime + 3%; $250,001–$350,000, Prime + 4.5%; $50,001–$250,000, Prime + 6%; $50,000 or less, Prime + 6.5% (13 CFR 120.214). The cap protects you from an excessive markup at origination, but a variable 7(a) rate still rises and falls with Prime. If you want a ceiling on the rate itself, ask for a lifetime cap in the note.

Fixed vs. Variable: How to Choose

The fundamental tradeoff:

• Fixed rate: Certainty. Your payment doesn't change regardless of market rates. You pay a premium at origination for that certainty.
• Variable rate: Lower initial rate. If benchmarks fall, you benefit automatically. If benchmarks rise, your payment increases.

The right choice depends on your rate outlook, your cash flow sensitivity to payment changes, and your loan term. For short-term loans (under 3 years), variable is often preferable. For long-term loans in a rising-rate environment, fixed provides meaningful protection.

Rate benchmarks like SOFR directly shape the annual percentage rate (APR) on your loan — the number that lets you compare the true cost across different lenders and products. If you're evaluating a commercial property loan, also review how your debt service coverage ratio (DSCR) interacts with current benchmark rates to determine what you qualify for.

Ready to move forward? start your loan application and connect with a specialist who can match you with the right loan program.

💡 BestLoanUSA can help you evaluate fixed vs. variable rate options for your specific financing need. Use our commercial loan calculators to model different scenarios before you apply. Pre-screen with no credit impact.

Sources: SBA 7(a) maximum variable rates — 13 CFR 120.214; alternative 7(a) base rates (SOFR, 5- and 10-year Treasury), effective March 1, 2026 — SBA Procedural Notice 5000-875051 and Federal Register, Feb. 10, 2026; SOFR — Federal Reserve Bank of New York; Prime and SOFR values — FRED snapshot. Payment changes computed with the site's loan payment formula.