The SOFR Index on a Business Loan: How Term SOFR Sets Your Variable Rate

If your variable-rate business loan was written in the last few years, open the note and look at the rate section. Where an older loan would have said “one-month LIBOR plus 3.00%,” yours probably says “one-month Term SOFR plus a margin” or “Daily Simple SOFR plus a margin.” That swap is not cosmetic. It changed the exact number your lender plugs in every month, and it is worth understanding what that number is, where it comes from, and why it is not something your lender gets to invent.

What SOFR actually is

SOFR stands for the Secured Overnight Financing Rate. It is a broad measure of what it costs to borrow cash overnight using U.S. Treasury securities as collateral — the repurchase (“repo”) market. The Federal Reserve Bank of New York publishes SOFR every business day, based on actual transaction volume in that market, typically more than a trillion dollars of trades a day. Because it is built on real, observed transactions rather than survey estimates, it is hard to manipulate.

That last point is the whole reason it exists. The rate it replaced, LIBOR, was set from banks’ own submitted estimates of their borrowing costs, and that system was found to be vulnerable to manipulation. Regulators pushed the market toward a transaction-based benchmark, and in the United States the Alternative Reference Rates Committee — a group convened by the Federal Reserve and the New York Fed — recommended SOFR as the replacement.

SOFR vs. Term SOFR: the distinction that matters to you

Here is where borrowers get tripped up. Plain SOFR is an overnight rate — it tells you the cost of money for a single night, and it is only known after the fact. A loan payment, by contrast, needs to be set at the start of a period so you know what you owe. Two different solutions emerged, and your note uses one of them:

• Term SOFR. A forward-looking rate — a 1-month, 3-month, 6-month, or 12-month rate — published by CME Group, derived from SOFR futures markets. It is set at the start of the period, so on the reset date you know your rate for the whole month or quarter ahead. This is the most common choice on business loans because it behaves like old LIBOR: one number, known in advance.
• Daily Simple SOFR (or Daily Compounded SOFR). Here the lender averages the actual daily SOFR over the period in arrears. It is more precise but you do not know the exact figure until the period is nearly over, which makes budgeting harder.

Most small-business term loans and lines that reset monthly or quarterly use Term SOFR. If your note names “Term SOFR,” the rate for your current period is already fixed and knowable — you do not have to wait.

How your actual rate is built

SOFR — in whatever flavor — is only the index. Your contract rate is the index plus a fixed margin (also called a spread) that your lender set at closing based on your credit, collateral, and the loan type. That margin does not change when the index moves. So the arithmetic each reset is simple:

Your rate = Term SOFR (for your tenor) + your fixed margin

Say your note is “3-month Term SOFR plus 3.25%.” If 3-month Term SOFR is sitting around 4%, your contract rate for the quarter is roughly 7.25%. When the quarter resets and Term SOFR has moved to 3.5%, your rate becomes about 6.75% — the margin never budged. This is the same structure as a prime-based loan, just with a different index. If you also have a prime-based loan, you now have two different benchmarks moving your payments, and they do not move in lockstep.

The reset or adjustment period

Your note specifies how often the rate recalculates — monthly, quarterly, annually — and on which day it reads the index. Between reset dates, your rate is locked even if SOFR swings wildly. This is why the adjustment period matters as much as the index: a loan that resets annually can shield you from a mid-year spike that a monthly-resetting loan would pass straight through. Read your note for the exact reset mechanics; do not assume.

The spread adjustment on converted LIBOR loans

If you have an older loan that was originally written on LIBOR and later moved to SOFR, there is one more wrinkle. SOFR is a secured rate and historically runs a touch lower than LIBOR, which carried bank credit risk. To keep the transition roughly rate-neutral, converted loans typically add a small fixed spread adjustment on top — a figure set by the ARRC’s recommended conventions and, for certain legacy contracts, by the federal LIBOR Act and the Federal Reserve’s implementing rule. The headline amounts differ by tenor, but the point for you is: on a converted loan, your “SOFR” rate may actually be Term SOFR + spread adjustment + margin. Check whether that middle term is in your note.

What this means for your payment and your planning

A variable rate is a shared bet on where short-term rates go. SOFR tracks the Federal Reserve’s policy stance closely — when the Fed moves its target range, SOFR tends to follow within the same window. Practically:

• You carry the rate risk, not the lender. If short-term rates rise, your payment rises at the next reset. Budget for that, do not assume today’s rate is permanent.
• Stress-test before you sign. Model your payment at two or three points higher than today’s rate and confirm the business still covers it. This is the same discipline we walk through for SBA variable loans, and it applies to any SOFR-indexed note.
• Check for a floor. Many notes include an interest rate floor — a minimum rate below which your loan cannot fall no matter how low SOFR goes. If the index drops, you may not get the full benefit.
• Know your tenor. 1-month Term SOFR and 3-month Term SOFR are different numbers. Your note names one; use that one when you do your own math.

How to verify your rate yourself

You do not have to take the lender’s word for the index value. SOFR is public. The New York Fed posts the daily SOFR on its reference-rates page. CME Group publishes the daily Term SOFR rates by tenor. On your reset date, pull the published figure for your exact tenor, add your margin (and any spread adjustment), and compare it to what the lender billed. If the numbers do not line up, you have a specific, documented question to raise — and because the benchmark is public, it is a question with a verifiable answer.

That verifiability is the quiet upside of the whole LIBOR-to-SOFR shift. The index behind your loan is now a published, transaction-based number anyone can look up, rather than something assembled behind closed doors. It does not make a variable loan cheaper or safer, but it does mean the figure moving your payment is one you can check.

The takeaway

SOFR is the benchmark; Term SOFR plus your fixed margin is your rate. The margin is locked, the index floats, and the reset period decides how fast changes reach your payment. Read your note for three things — the exact tenor, the reset frequency, and whether a spread adjustment or a rate floor is baked in — and you will know precisely how your payment is built and how to check it every period.

Important: MidBank is not a bank, a financial institution, or a financial advisor. We are an advocate and ISO affiliate that connects businesses to vetted third-party providers. This article is general information published on November 9, 2026, not legal, tax, or financial advice — rules and rates change, and your situation is specific to you. Confirm details with the primary sources linked above and with a qualified tax or legal professional before acting.