What it means
A government bond is treated as the lowest-risk benchmark for lending money over a given term. A swap rate for the same term reflects the cost of funding for banks and other large financial firms.
The gap between the two is the swap spread. Historically the swap rate sat above the government yield, because banks were seen as slightly riskier than the government and the spread paid for that extra risk.
In times of stress the spread widened as worries about banks grew. More recently, in some markets and at longer maturities, the spread has turned negative, driven by regulation, demand for government bonds and the cost of holding them.
The swap spread matters in practice because many companies price fixed-rate funding off swaps while investors price government bonds directly. If the spread widens, a company that issues a bond priced off government yields may see the swap market offer a different cost for the same exposure.
Traders also use spread trades, where they take opposite positions in a swap and a government bond, to bet on the gap moving. Reading the spread requires care about what sits behind it.
It combines credit risk, supply and demand for government bonds, how banks fund themselves, and the regulatory capital that firms must hold against each position. A move in the spread therefore does not always mean the same thing.
Finally, the spread depends on the floating rate benchmark used in the swap. Because those benchmarks have changed over the years, comparisons across time need to use consistent definitions.
It helps to remember that the spread is a relative measure, not a level of interest rates. Both the swap rate and the government yield can rise together while the spread stays the same.
Treasurers therefore look at the spread when they want to compare funding routes, and at the outright swap rate when they want to know what a hedge will cost in total.
In practice
Real-world examples.
Example
A fund manager believes bank funding stress is easing and expects the spread to narrow. She takes a position that profits if the swap rate falls relative to the government yield, and sizes it so that each basis point is worth $5,000.
Example
A utility company plans a ten-year fixed-rate bond issue. Its treasurer notes that swap spreads have widened, so fixing the rate through a swap would now cost more than the government yield alone suggests, and adjusts the pricing plan.
Example
A bank's risk team reports a sudden jump in the two-year swap spread to its board. The note explains that the move reflects tighter interbank funding rather than a change in government borrowing costs.
Formula
Calculation
Swap spread = Swap rate - Government bond yield (same maturity)
Suppose the ten-year swap rate is 4.30% and the ten-year government bond yield is 4.05%.
Swap spread = 4.30% - 4.05% = 0.25%, which is 25 basis points.
If a month later the swap rate is 4.40% and the bond yield is 4.30%, the spread is 4.40% - 4.30% = 0.10%, or 10 basis points. The spread has narrowed by 25 - 10 = 15 basis points.
On a $20,000,000 position, one basis point is worth $20,000,000 x 0.0001 = $2,000, so a 15 basis point move represents $2,000 x 15 = $30,000.Case study
Seen in the real world.
Meridian Capital is an illustrative, fictional asset manager that holds a large portfolio of government bonds and uses swaps to manage its interest rate exposure. The risk committee noticed that the five-year swap spread had narrowed from 30 basis points to 12 over three months.
The analyst team explained that demand for government bonds had pushed their yields down relative to swap rates. For Meridian this mattered because its hedges were priced off swaps while its assets were priced off government yields, so the hedge was no longer tracking the bonds as closely.
In the illustrative outcome the committee adjusted the hedge ratio and added a monitoring line for the spread. The lesson is that a hedge can be correct in direction and still leak money when the relationship between the two benchmarks moves.
Watch out
Common mistakes.
- Assuming the swap spread is always positive, when it can turn negative at some maturities.
- Reading a wider spread as purely a sign of bank credit worries, when supply, demand and regulation also move it.
- Comparing spreads across different floating benchmarks or maturities without checking that the definitions match.
Questions
People also ask.
Is a swap spread the same as a credit spread?
No, a credit spread compares a corporate bond yield with a government yield, while a swap spread compares a swap rate with a government yield.
Why is it quoted in basis points?
Because the differences are small, and one basis point is one hundredth of a percentage point, which makes comparisons precise.
Who uses swap spreads?
Bond traders, bank treasurers, pension funds and corporate treasurers all use them to judge relative value and funding costs.
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