BondTerminal

What is a bond spread?

Spread is the bond market's risk thermometer. The same bond can have three different spreads depending on which method you use.

The direct answer

A bond spread is the yield difference between a corporate or sovereign bond and a benchmark — almost always a comparable-maturity US Treasury for USD-denominated debt. It is the market's price of credit, illiquidity, and term risk above the (assumed) risk-free curve.

There are three common spread measures: G-spread (the simplest), Z-spread (more rigorous), and OAS (handles embedded options). They agree on the sign of the answer but can differ by tens of basis points.

The three main spreads

SpreadWhat it isWhen to use
G-spreadBond YTM minus the YTM of an interpolated Treasury of the same maturity.Quick comparison; what most screens show by default.
Z-spreadConstant parallel shift to the Treasury zero curve that re-prices the bond at its market price.More accurate when the curve is steep; common for credit analysis.
OASZ-spread adjusted for the value of embedded options (calls, puts).Required for callable or putable bonds — otherwise spread looks artificially wide or tight.

Argentina-specific notes

Argentina's sovereign USD bonds are typically discussed in terms of riesgo país, an JPMorgan EMBI-style spread quoted in basis points over US Treasuries. It is conceptually close to a weighted G-spread across the sovereign curve, not the spread of a single bond.

When sovereign risk premia move fast (election windows, IMF news), the gap between G-spread, Z-spread, and OAS for the same bond can widen meaningfully. Use OAS for callable bonds like GD35 and GD46 to avoid double-counting the call risk in the spread.

Frequently asked questions

Which spread does BondTerminal show on the calculator?
BondTerminal's calculator shows G-spread by default for clarity and consistency with most market screens. We compute against an interpolated US Treasury curve refreshed from Treasury.gov; the curve date is shown alongside the spread so you can sanity-check against a stale day.
Why does riesgo país differ from a single bond's G-spread?
Riesgo país is a portfolio measure across the Argentina USD sovereign curve, not a single bond. It weights individual G-spreads roughly by outstanding amount and duration, so it sits between the tightest and widest single-bond spreads. See our riesgo país methodology for the exact formula we apply.
What does a negative spread mean?
It is possible for a high-quality corporate or supranational to trade through Treasuries — i.e., a negative spread to the curve. This usually reflects scarcity, regulatory demand (banks holding HQLA), or temporary supply/demand imbalances rather than the issuer being safer than the US government.
Why does a callable bond's spread look wide on BondTerminal?
We currently surface G-spread on callable bonds, which incorporates the call optionality into a wider apparent spread. For investment decisions on callable Argentina sovereigns (e.g., GD35, GD46), compare to the same-maturity non-callable peers and consider OAS when available.

Related resources