Credit Portfolio Management: Ch 6 Flashcards
Option Adjusted Spread (OAS)
Measurement of the spread of a fixed-income security rate and the risk-free rate
of return, which is adjusted to take into account an embedded option
Uses of Spread Decomposition
- Can help portfolio managers understand spread movements better
- Investors can use spread decomposition for:
- Hedging
- Forecasting future OAS changes
- Developing alpha strategies
- The portfolio strategy will depend on the reason why the credit spread moved. For example, whether the wide spreads are due to large expected default losses, high liquidity cost or a high-risk premium
- The portfolio can ride out periods of high liquidity cost and risk aversion if a buy-and-hold strategy is used.
- If the wide spread reflects an increase in expected default losses, you may need to reposition or hedge its portfolio.
Risk Premium in Spread Decomposition
- Represents the market-level risk premium and not a risk premium specific to each bond
- Represents the variation of the market risk premium that is not already embedded in the other variables (e.g. LCS, CDS)
- When the intercept explains a relatively high proportion of OAS, it suggests that systematic factors rather than bond-specific factors are driving spreads
- When intercept getting larger and coefficients getting smaller
Expected Default Cost in Spread Decomposition
- Part of the OAS is driven by the possibility of default and the recovery level of defaults
- Two Models used to quantify expected default cost: CDS and CDP/CRR
Credit Default Swap (CDS) Model
- Expected Default Costit = CDSit
- Use market-quoted five-year CDS as a measure of expected default cost
- Generally the five year point is most liquid
- Restrict analysis to CDX Index
- CDX Index - an index comprised of the most liquid North American entities that trade in the CDS market
CDP/CRR Model
- Expected DefaultCostit = CDPit * (1 - CRRit)
- CDP = Conditional Default Probability
- CRR = Conditional Recovery Rate
- CDP, CRR are not market variables
- Calculated from a firm-specific macroeconomic model
- Computed independently of a bond’s OAS
Expected Liquidity Cost
- The Expected Liquidity Cost calculated will use the Liquidity Cost Score (LCS) model from Chapter 5
Overlap b/w Expected Default Cost and Expected Liquidty Cost
- Another portion of the OAS is from the degree of uncertainty associated with the timing, magnitude, and recovery of defaults and liquidity costs
- The author states that credit bond spreads are generally much larger than is justified by their subsequent default and recovery experience
- If an investor seeks to hedge the default or liquidity components separately, then the contribution to OAS in bps is relevant
- If an investor is analyzing current market compensation for taking on additional amounts of expected default or liquidity cost, the coefficients provide that information
Spread Decomposition Methodology/Models
Interpreting Results of Spread Decomposition Methodology
- First add the expected default cost component through CDS or CDP/CRR
- Then add LCS
- Should see that adding LCS does not substantially change the CDS or CDP/CRR coefficient and an improvement in R-squared if LCS is a useful explanatory variable
- Expect statistically signficant coefficients both with positive signs for beta
and lamda
Multicollinearity in Spread Decomposition
- When regressors are added in one-by-one in a multi-step regression analysis, the coefficients should not change substantially when new regressors are added.
- For example, the CDS coefficient should be similar in the CDS-only model and the LCS & CDS model.
- If there are substantial changes to coefficient values of existing regressors when new regressors are added, this could indicate multicollinearity problems.
Disadvantages of the Spread Decomposition Methodology
- Liquidity and default are unlikely to be completely independent of each other, so multicollinearity may be a concern. Recall that multicollinearity is when two or more predictor variables in a regression model are highly correlated
- If the CDS model is used, the CDS market may not necessarily be liquid and therefore cannot always be considered as a pure default proxy
Advantages and Disadvantages of CDP/CRR Model
Advantages of CDP/CRR Model:
- CDP and CRR are independent of market spreads
- Larger sample, because CDP/CRR data spans over a larger supply of tickers than the number of CDS in the CDX
Disadvantages of CDP/CRR Model:
- Market CDS spreads are likely to be more closely related to OAS than to a modeled default probability estimator. This advocates the CDS model over the CDP/CRR model
- In the dataset the author uses, the CDP/CRR coefficient changes (more significantly than the CDS model) when LCS is included as an additional variable.
- stronger multicollinearity b/w CDP/CRR and LCS
High Yield Spread Decomposition
- Compared to investment grade bonds, default risk will play a relatively bigger role for the spread decomposition of high yield bonds
- Liquidity cost provides additional explanatory power in high-yield spreads only during period of market stress in the data set the author analyzes
- The intercept is larger for high yield, suggesting that risk aversion, unrelated to liquidity/default characteristics, may drive a large proportion of yield spreads
Applications of Spread Decomposition: Ex-Ante Analysis
- Bond’s market OAS can be compared with estimated OAS using the parameters from the spread decomposition model
- If the actual OAS is wider than the estimated OAS, the bond may be trading too wide. This difference will be captured in the initial residual ˆhit
- This could cause a trading signal to reverse the mispricing and (theoretically) more closely align the actual and estimated OAS