Zhan Shi

Bio: Zhan Shi is an academic researcher from Tsinghua University. The author has contributed to research in topics: Credit risk & Bond. The author has an hindex of 5, co-authored 11 publications receiving 121 citations. Previous affiliations of Zhan Shi include Pennsylvania State University.

Specification Analysis of Structural Credit Risk Models

Abstract: In this paper we conduct a specification analysis of structural credit risk models, using term structure of credit default swap (CDS) spreads and equity volatility from high-frequency return data. Our study provides consistent econometric estimation of the pricing model parameters and specification tests based on the joint behavior of time-series asset dynamics and cross-sectional pricing errors. Our empirical tests reject strongly the standard Merton (1974) model, the Black and Cox (1976) barrier model, and the Longstaff and Schwartz (1995) model with stochastic interest rates. The double exponential jump-diffusion barrier model (Huang and Huang, 2003) improves significantly over the three models. The best one among the five models considered is the stationary leverage model of Collin-Dufresne and Goldstein (2001), which we cannot reject in more than half of our sample firms. However, our empirical results document the inability of the existing structural models to capture the dynamic behavior of CDS spreads and equity volatility, especially for investment grade names. This points to a potential role of time-varying asset volatility, a feature that is missing in the standard structural models.

Determinants of Bond Risk Premia

Abstract: In this paper, we provide new and robust evidence on the power of macro variables for forecasting bond risk premia. Specifically, we identify a single macro factor that can explain the variation in excess returns on bonds with maturities ranging from 2 to 5 years up to 43%, substantially higher than the 26%-R 2 obtained using the macro factor of Ludvigson and Ng (2008), and that also subsumes the LudvigsonNg factor. In addition, we find that augmenting regressions of excess bond returns on the identified macro factor with lagged bond excess returns can raise the R 2 to 88%. The source of predictability from the macro factor is found to be associated with variables from employment, housing market and price indices. We are able to identify such robust macro factor with strong predicting power by using a recently developed statistical method‐the supervised adaptive group “least absolute shrinkage and selection operator” (lasso) approach.

The Global Credit Spread Puzzle

Abstract: Using security-level credit spread data in eight developed economies, we document a large cross-country difference in credit spreads conditional on credit ratings and other default risk measures. The standard structural models not only fail to explain this cross-country variation in spreads but also have difficulty predicting credit spreads accurately. We implement an extended structural model that incorporates endogenous liquidity in the secondary market and find that this model largely explains credit spreads in the cross section and over time, as well as significantly reduces pricing errors. Therefore, default risk itself is an unlikely explanation for international corporate bond spreads.

How Much of the Corporate-Treasury Yield Spread Is Due to Credit Risk?

Abstract: We show that credit risk accounts for only a small fraction of yield spreads for investment-grade bonds of all maturities, with the fraction lower for bonds of shorter maturities, and that it accounts for a much higher fraction of yield spreads for high-yield bonds This conclusion is shown to be robust across a wide class of structural models We obtain such results by calibrating each of the models to be consistent with data on the historical default loss experience and equity risk premia, and demonstrating that different models predict similar credit risk premia under empirically reasonable parameter choices

Rollover Risk and Credit Risk

Abstract: Our model shows that deterioration in debt market liquidity leads to an increase in not only the liquidity premium of corporate bonds but also credit risk. The latter effect originates from firms’ debt rollover. When liquidity deterioration causes a firm to suffer losses in rolling over its maturing debt, equity holders bear the losses while maturing debtholdersare paidinfull.Thisconflictleadsthefirmto defaultatahigher fundamental threshold. Our model demonstrates an intricate interaction between the liquidity premium and default premium and highlights the role of short-term debt in exacerbating rollover risk. THE YIELD SPREAD OF a firm’s bond relative to the risk-free interest rate directly determines the firm’s debt financing cost, and is often referred to as its credit spread. It is widely recognized that the credit spread reflects not only a default premium determined by the firm’s credit risk but also a liquidity premium due to illiquidity of the secondary debt market (e.g., Longstaff, Mithal, and Neis (2005) and Chen, Lesmond, and Wei (2007)). However, academics and policy makers tend to treat both the default premium and the liquidity premium as independent, and thus ignore interactions between them. The financial crisis of 2007 to 2008 demonstrates the importance of such an interaction— deterioration in debt market liquidity caused severe financing difficulties for many financial firms, which in turn exacerbated their credit risk. In this paper, we develop a theoretical model to analyze the interaction between debt market liquidity and credit risk through so-called rollover risk: when debt market liquidity deteriorates, firms face rollover losses from issuing new bonds to replace maturing bonds. To avoid default, equity holders need to bear the rollover losses, while maturing debt holders are paid in full. This

The Components of Corporate Credit Spreads: Default, Recovery, Tax, Jumps, Liquidity, and Market Factors - eScholarship

Abstract: This paper analyzes the components of corporate credit spreads. The analysis is based on a structural model that can offer a framework to understand the decomposition. The paper contends that default risk may correctly represent only a small portion of corporate credit spreads. This idea stems both from empirical evidence and from the following theoretical assumptions underlying contingent claim models of default: that markets for corporate stocks and bonds are (i) perfect, (ii) complete, and (iii) trading takes place continuously. Thus, in these models there are no transaction or bankruptcy costs, no tax effects, no liquidity effects, no jump effects reflecting market incompleteness, and no market risk factors effecting the pricing of corporate stocks or bonds. The paper starts with the use of a modified version of the Black-Scholes-Merton diffusion based option approach. We estimate corporate default spreads as simply a component of corporate credit spreads using data from November 1991 to December 1998, which includes the Asian Crisis in the Fall, 1998. First we measure the difference between the observed corporate credit spreads and option based estimates of default spreads. We define this difference as the residual spread. We show that for AAA (BBB) firms only a small percentage, 5% (22%), of the credit spread can be attributed to default risk. We show that recovery risk also cannot explain this residual spread. Next, we show that state taxes on corporate bonds also cannot explain the residual. We note that the pure diffusion assumption may lead to underestimates of the default risk. In order to include jumps to default, we next estimate what combined jump-diffusion parameters would be necessary to force default spread to eliminate the residual spread. In each rating class on average firms would be required to experience annual jumps that decrease firm value by 20% and increase stock volatility by more than 100% over their observed volatility in order to eliminate the residual spread. We consider this required increase in stock volatility to be unrealistic as the sole explanation of the residual spread. So next we consider whether the unexplained component can be partly attributable to interest rates, liquidity, and market risk factors. We find the following empirical results: i) increases in liquidity as measured by changes in each firm’s trading volume significantly reduces the residual spread, but does not alter the default spread; ii) increases in stock market volatility significantly reduces the residual spread by increasing the default spread relative to the credit spread, and iii) increases in stock market returns significantly increases the residual spread by reducing the default spread relative to the credit spread. This paper concludes that credit risk and credit spreads are not primarily explained by default and recovery risk, but are mainly attributable to taxes, jumps, liquidity, and market risk factors.

Rollover Risk and Credit Risk

Abstract: Our model shows that deterioration of debt market liquidity not only leads to an increase in liquidity premium of corporate bonds but also credit risk. The latter effect originates from firms' debt rollover. When liquidity deterioration causes a firm to suffer losses in rolling over its maturing debt, equity holders bear the losses while maturing debt holders get paid in full. This conflict leads the firm to default at a higher fundamental threshold. Our model demonstrates an intricate interaction between liquidity premium and default premium and highlights the role of short-term debt in exacerbating rollover risk.