Yield basis, also known as yield spread or yield differential, is a measure used in financial markets to assess the relative value of different fixed-income securities. It represents the difference in yield between two securities or benchmarks and is calculated by subtracting the yield of one security from the yield of another.
The calculation of yield basis depends on the specific context and purpose. Here, we will discuss two common methods: nominal yield basis and option-adjusted spread (OAS).
1. Nominal Yield Basis:
Nominal yield basis is a straightforward calculation that compares the yields of two fixed-income securities. It is commonly used to compare bonds with similar characteristics, such as maturity and credit quality. The formula for nominal yield basis is as follows:
Yield Basis = Yield of Security A - Yield of Security B
For example, if Security A has a yield of 4% and Security B has a yield of 3%, the nominal yield basis would be 1% (4% - 3%).
2. Option-Adjusted Spread (OAS):
OAS is a more sophisticated measure that takes into account the embedded options in certain fixed-income securities, such as callable or putable bonds. These options give the issuer or bondholder the right to buy back or sell the bond before maturity, which affects the bond's cash flows and, consequently, its yield.
To calculate OAS, a model is used to estimate the value of the embedded options and adjust the yield accordingly. The OAS represents the spread over a risk-free
benchmark that compensates investors for the additional risk associated with the embedded options. A positive OAS indicates that the security offers a higher yield compared to the risk-free benchmark.
Factors influencing yield basis:
Several factors can influence the value of yield basis:
1. Credit risk: The
creditworthiness of the issuer affects the yield of a security. Higher credit risk typically leads to higher yields, resulting in a wider yield basis.
2. Maturity: Longer-term securities generally have higher yields compared to shorter-term securities due to the increased uncertainty associated with longer time horizons. Consequently, the yield basis may widen for securities with longer maturities.
3.
Liquidity: Less liquid securities tend to have higher yields to compensate investors for the additional risk of not being able to easily sell the security. This can impact the yield basis when comparing liquid and illiquid securities.
4. Market conditions: Changes in overall market conditions, such as
interest rate movements or shifts in investor sentiment, can influence yield basis. For example, if interest rates rise, the yield of fixed-income securities tends to increase, resulting in a wider yield basis.
5. Supply and demand dynamics: The relative supply and demand for specific securities can impact their yields and, consequently, the yield basis. If demand for a particular security increases, its yield may decrease relative to other securities, narrowing the yield basis.
In conclusion, yield basis is calculated by subtracting the yield of one security from another and can be measured using nominal yield basis or option-adjusted spread (OAS). Various factors, including credit risk, maturity, liquidity, market conditions, and supply and demand dynamics, influence the value of yield basis in financial markets.