How this instrument works
A credit spread is the gap between what a corporate bond yields and what a government bond of the same maturity yields, restated in basis points instead of a raw percentage difference. It isolates the slice of a corporate bond's return that exists purely because the issuer is not a government: hold maturity, currency, and coupon structure constant, and the corporate bond still has to pay more to attract a buyer who could instead own something the market treats as close to default-free. That extra pay is compensation for one thing — the chance the corporate issuer misses a payment or restructures its debt — and the spread is the market's running estimate of how large that chance is, priced in real time by every buyer and seller trading the bond.
Credit analysts and bond portfolio managers watch this number to rank issuers against each other and against their own history — a spread of 80 to 150 basis points is typical territory for investment-grade corporates, 300 to 500 basis points is common for high-yield issuers, and spreads above 1,000 basis points usually mark a bond the market considers distressed. Corporate treasurers track their own company's spread the same way bond desks do, because it is a live readout of what the market thinks their next debt issue will cost. The formula itself is deliberately plain: subtract the Treasury yield from the corporate yield, then multiply by 100 so a small percentage-point gap reads as a whole number of basis points rather than a decimal most people misread at a glance.
The arithmetic assumes you already matched the two bonds by maturity; pair a 10-year corporate against a 2-year Treasury and the spread mixes credit risk with the shape of the yield curve, no longer isolating default risk alone. It also reports a nominal spread, not the option-adjusted spread a bond terminal shows for a callable or convertible issue — those instruments carry embedded options that this simple subtraction does not strip out. And a spread by itself never says whether the market is pricing the issuer's risk correctly; it only reports what the market currently charges, which can lag a deteriorating balance sheet or overreact to a single bad headline.
- Enter Corporate bond yield, % — the yield to maturity quoted for the specific corporate bond you're evaluating.
- Enter Treasury (risk-free) yield, % — the yield on a government bond with the closest matching maturity, used as the risk-free benchmark.
- Read Credit spread, basis points — the gap between the two, computed instantly as you adjust either figure.
- Compare the result against typical ranges for the issuer's rating tier to judge whether the market prices it as safe or risky relative to peers.
- Recheck both yields against the same date — spreads built from yields quoted on different days mix market noise into the comparison.
Worked example — 6.5% corporate against a 4.2% Treasury
Take the sheet's default pair: a corporate bond yielding 6.5% and a Treasury of matching maturity yielding 4.2%. Subtracting gives 6.5 − 4.2 = 2.3 percentage points, and multiplying by 100 converts that into basis points: spread = 2.3 × 100 = 230 bps, the exact figure this instrument returns for those two inputs.
230 basis points sits near the boundary between investment-grade and high-yield territory — comfortably wider than the 80-to-150 range typical of a strong BBB issuer, but nowhere near the 800-plus basis points a genuinely distressed borrower can show against the same Treasury. A bond desk watching this number over time cares less about the single reading than the direction: if the Treasury yield holds steady at 4.2% and the corporate yield drifts up toward 7.5%, the spread widening past 330 basis points signals the market reassessing this specific issuer's risk, not a broader move in interest rates.
Questions
What does a credit spread actually measure?
It measures how much extra yield investors demand to hold a corporate bond instead of a government bond of the same maturity — compensation for the chance the corporate issuer misses a payment or restructures its debt. A wider spread means the market is pricing in more perceived risk; a narrower one means the market treats the issuer as nearly as safe as the government benchmark.
Why state the difference in basis points instead of percent?
Because the gap between two bond yields is usually a small fraction of a percentage point, and basis points give that fraction a whole number instead of a decimal that is easy to misread. A move from 2.3% to 2.5% looks trivial written as percent but is a 20 basis point widening — a size fixed-income desks track closely, since moves of that scale routinely separate a stable issuer from one the market is starting to worry about.
What counts as a normal credit spread?
It depends entirely on credit quality. Strong investment-grade corporates typically trade 80 to 150 basis points over Treasuries, high-yield issuers commonly run 300 to 500 basis points wider, and spreads above roughly 1,000 basis points usually mark a bond the market considers distressed. These ranges shift with the economic cycle — they compress when investors feel confident and widen sharply when default fears rise across the board, not just for one issuer.
Why did my bond's spread move even though its yield didn't change?
Because the spread depends on both yields, and the Treasury side moves on its own for reasons that have nothing to do with the corporate issuer — a Federal Reserve rate decision, an inflation report, or a shift in demand for government debt. If the Treasury yield falls while the corporate yield holds steady, the spread widens even though the market's view of that specific company hasn't changed at all; check which side moved before reading anything into it.
Is this the same as the option-adjusted spread on a bond terminal?
No. This is a nominal spread — a straight subtraction of one yield from another. Option-adjusted spread strips out the value of any call, put, or conversion feature embedded in the bond before comparing it with the Treasury curve, which matters for callable corporate bonds where the option itself changes the yield. For a plain, non-callable bond the two numbers sit close together; for a callable one, expect them to diverge.
Do the two bonds need to share the same maturity?
Yes, or as close to it as available. Treasury yields differ by maturity — the yield curve itself has shape — so pairing a 10-year corporate bond against a 2-year Treasury blends genuine credit risk with the unrelated fact that longer and shorter government debt yield differently. Match maturities as closely as the market lets you, or the spread stops isolating default risk alone.
References
- SEC Investor.gov — Bonds or fixed income products
- Federal Reserve — Selected interest rates (H.15 release)
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.