Bond Yields, Ratings, and Financial Information: Evidence from Public Utility Issues

This study investigates the relative roles of bond ratings and financial information in the setting of bond yields. Structural equation modeling techniques are used to learn whether ratings determine yields or whether both ratings and yields are determined by a concurrent set of economic and financial factors. Tests of alternative structural model configurations provide evidence regarding the associations between bond ratings, financial information, and bond yields. Both ratings and financial information are found to play an important role in determining bond yields. In addition, yields are consistent with the higher rating in cases of split ratings.     

On the consistency of ratings and bond market yields

We study the consistency of the credit-risk orderings implicit in ratings and bond market yields. By analyzing errors in term structure estimates for bonds with particular ratings, we show that for significant periods, a quarter of some categories of high credit quality bonds are rated in a manner that is inconsistent with their pricing. Adjusting for economic determinants of spreads (tax, liquidity and risk premiums) and allowing for the dynamic adjustment of ratings and spreads largely eliminates the inconsistencies, however.     

Conditioning Information and European Bond Fund Performance

In this paper we evaluate the performance of European bond funds using unconditional and conditional models. As conditioning information we use variables that we find to be useful in predicting bond returns in the European market. The results show that, in general, bond funds are not able to outperform passive strategies. These findings are robust to whatever model (unconditional versus conditional and single versus multi‐index) we use. The multi‐index model seems to add some explanatory power in relation to the single‐index model. Furthermore, when we incorporate the predetermined information variables, we can observe a slight tendency towards better performance. This evidence is consistent with previous studies on stock funds and comes in support of the argument that conditional models might allow for a better assessment of performance. However, our results suggest that the impact of additional risk factors seems to be greater than the impact of incorporating predetermined information variables.     

Determinants of the Dollar Value of Default Risk: A Put Option Perspective

This study uses the option valuation framework to identify andinvestigate the factors affecting the cross-sectional difference inindividual corporate bonds' default risk. The dollar value of defaultrisk (DVDR) is measured by subtracting the observed trading price of arisky corporate bond from a Cox-Ingersoll-Ross model value of acorresponding pseudo-default-free bond. From an option pricingperspective, DVDR can be modeled as the value of a put option on thefirm's risky assets. The DVDR of an individual investment-grade corporatebond is hypothesized to be related to the bond rating, time to maturity ofthe bond, size of the issuing firm, volatility of firm value, and dividendyield of the issuing firm. In the case of the first four factors, theempirical results are consistent with the predictions from a put optionperspective. There is a mixed relationship between DVDR and dividendyield, however, which provides a weaker support for the prediction of theoption valuation model. Such a mixed relationship documents the importantrole that dividend payments play in signaling a firm's future earnings andreducing overall agency costs. ["In particular, the formula can be usedto derive the discount that should be applied to a corporate bond becauseof the possibility of default." (Black and Scholes (1973), Journal of Political Economy, Abstract, p. 637.)]     

Combining Bond Rating Forecasts Using Logit

Companies sometimes use statistical analysis to anticipate their bond ratings or a change in the rating. However, different statistical models can yield different ratings forecasts, and there is no clear rule for which model is preferable. We use several forecasting methods to predict bond ratings in the transportation and industrial sectors listed by Moody's bond rating service. A variant of the ordered‐logit regression‐combining method of Kamstra and Kennedy 1998 yields statistically significant, quantitatively meaningful improvements over its competitors, with very little computational cost.     

THE INFORMATIONAL ROLE OF BANK LOAN RATINGS

We analyze the relatively new phenomenon of credit ratings on syndicated loans, asking first whether they convey information to the capital markets. Our event studies show that initial loan ratings and upgrades are not informative, but downgrades are. The market anticipates downgrades to some extent, however. We also examine whether public information reflecting borrower default characteristics explains cross‐sectional variation in loan ratings and find that ratings are only partially predictable. Our evidence suggests that loan and bond ratings are not determined by the same model. Finally, we estimate a credit spread model incorporating bank loan ratings and other factors reflecting default risk, information asymmetry, and agency problems. We find that ratings are related to loan rates, given the effect of other influences on yields, suggesting that ratings provide information not reflected in financial information. Ratings may capture idiosyncratic information about recovery rates, as each of the agencies claims, or information about default prospects not available to the market.     

Split Bond Ratings and Information Opacity Premiums

This paper examines the relationship between split bond ratings and bond yields at the notch level for newly issued corporate bonds. We find that split rated bonds average a 7-basis-point yield premium over nonsplit rated bonds of similar credit risk. The yield premium increases from 5 basis points for one-notch splits to 15 (20) basis points for two-notch (three-notch) splits. These findings indicate that investors demand higher yields for split rated bonds to compensate for the information opacity of such bonds. In addition, the yield premium for split rated bonds is higher during economic recessions, indicating investors are more risk averse during economic downturns. Consequently, split ratings impose higher borrowing costs for firms, especially during economic downturns.     

Predictability of Emerging Market Local Currency Bond Risk Premia

This article investigates the source of predictability of emerging market (EM) local currency bond risk premia by using a dynamic factor approach based on a large panel of economic and financial time series. We find strong predictable variation in EM local currency excess bond returns that is associated with macroeconomic activity. We provide evidence that the main predictor variables are the factors based on real economic activity that are highly correlated with measures of industrial and manufacturing production; however, factors based on global financial factors also contain information about the future local currency bond returns. The predictive power of the extracted factors is both statistically significant and economically important. Our research has important implications for policymakers and pension fund managers.     

The ordered qualitative model for credit rating transitions

Information on the expected changes in credit quality of obligors is contained in credit migration matrices which trace out the movements of firms across ratings categories in a given period of time and in a given group of bond issuers. The rating matrices provided by Moody's, Standard & Poor's and Fitch became crucial inputs to many applications, including the assessment of risk on corporate credit portfolios (CreditVar) and credit derivatives pricing. We propose a factor probit model for modeling and prediction of credit rating matrices that are assumed to be stochastic and driven by a latent factor. The filtered latent factor path reveals the effect of the economic cycle on corporate credit ratings, and provides evidence in support of the PIT (point-in-time) rating philosophy. The factor probit model also yields the estimates of cross-sectional correlations in rating transitions that are documented empirically but not fully accounted for in the literature and in the regulatory rules established by the Basle Committee.     

基于套利理论与ICIR模型的债券市场发行定价偏离研究

基于套利定价理论与利率期限结构理论,运用Tobit多元线性回归模型,得出债券发行定价的主要影响因素为债券无风险利率、债券期限溢价、债项信用评级、债券主体信用评级和债券赎回风险溢价,在此基础上再通过改进的CIR定价模型(ICIR)对2006～2010年各债券定价偏离现象进行研究的结果表明,在1%的显著性水平上,ICIR模型测算的债券理论价格通过了二级市场的定价检验,ICIR模型对债券发行定价偏离进行检验具有较强的合理性;同时,从发行年份来看,近五年来,债券定价偏离总体呈逐年下降趋势,债券发行定价与ICIR定价与二级市场定价逐步接轨,市场化程度越来越高。     

Analysis of default data using hidden Markov models

The occurrence of defaults within a bond portfolio is modelled as a simple hidden Markov process. The hidden variable represents the risk state, which is assumed to be common to all bonds within one particular sector and region. After describing the model and recalling the basic properties of hidden Markov chains, we show how to apply the model to a simulated sequence of default events. Then, we consider a real scenario, with default events taken from a large database provided by Standard & Poor's. We are able to obtain estimates for the model parameters and also to reconstruct the most likely sequence of the risk state. Finally, we address the issue of global versus industry-specific risk factors. By extending our model to include independent hidden risk sequences, we can disentangle the risk associated with the business cycle from that specific to the individual sector.     

Liquidity,default, taxes,and yields on municipal bonds

We examine the effects of liquidity, default and personal taxes on the relative yields of Treasuries and municipals using a generalized model with liquidity risk. The municipal yield model includes liquidity as a state factor. Using a unique transaction dataset, we estimate the liquidity risk of municipals and its effect on bond yields. Empirical evidence shows that municipal bond yields are strongly affected by all three factors. The effects of default and liquidity risk on municipal yields increase with maturity and credit risk. Liquidity premium accounts for about 9–13% of municipal yields for AAA bonds, 9–15% for AA/A bonds and 8–19% for BBB bonds. A substantial portion of the maturity spread between long- and short-maturity municipal bonds is attributed to the liquidity premium. Ignoring the liquidity risk effect thus results in a severe underestimation of municipal bond yields. Conditional on the effects of default and liquidity risk, we obtain implicit tax rates very close to the statutory tax rates of high-income individuals and institutional investors. Furthermore, these implicit income tax rates are quite stable across bonds of different maturities. Results show that including liquidity risk in the municipal bond pricing model helps explain the muni puzzle.     

中国自然利率之谜与债券市场定价——基于宏观金融模型视角

关于发达国家的研究普遍存在使用标准金融模型估计的自然利率与宏观方法估计的自然利率不相符的“自然利率之谜”现象。本文分别使用金融模型和宏观半结构模型估计中国的自然利率,发现同样存在“自然利率之谜”现象。我们通过构建一致性的宏观金融模型,采用宏观经济变量和收益率曲线信息共同估计自然利率来解决这一问题。此外,寻找债券收益率的影响因子是债券定价研究的重要方面,宏观与金融模型的结合是债券定价研究的重要趋势。宏观金融理论表明,趋势通货膨胀和自然利率是收益率曲线的基本决定因素,在宏观金融框架下,我们进一步研究了自然利率对债券收益率的影响。研究结果表明:(1)宏观金融模型能很好地解决中国“自然利率之谜”问题,宏观金融模型估计得到的自然利率略低于宏观半结构模型的结果。(2)自然利率对债券收益率有显著影响,模型中增加自然利率信息能够提高对不同期限国债收益率的拟合优度。本文对进一步加强自然利率影响因素研究,运用一致性宏观金融模型得到的自然利率信息优化货币政策效果提供了参考。     

Pricing defaultable bonds: a middle-way approach between structural and reduced-form models

In this paper we present a valuation model that combines features of both the structural and reduced-form approaches for modelling default risk. We maintain the cause and effect or ‘structural’ definition of default and assume that default is triggered when a state variable reaches a default boundary. However, in our model, the state variable is not interpreted as the assets of the firm, but as a latent variable signalling the credit quality of the firm. Default in our model can also occur according to a doubly stochastic hazard rate. The hazard rate is a linear function of the state variable and the interest rate. We use the Cox et al. (A theory of the term structure of interest rates. Econometrica, 1985, 53(2), 385–407) term structure model to preclude the possibility of negative probabilities of default. We also horse race the proposed valuation model against structural and reduced-form default risky bond pricing models and find that term structures of credit spreads generated using the middle-way approach are more in line with empirical observations.     

The Independent Impact of Credit Rating Changes – The Case of Moody's Rating Refinement on Yield Premiums

On April 26, 1982, Moody's Investors Service refined its rating system for the first time in its seventy-three year rating history. We examine the information content of the rating refinement in the study. We find a statistically significant change in the yields on bonds whose ratings were downgraded. The detection of the impact of refinement on bond prices implies that rating agencies perform an important function in financial markets, that is they provide information to investors.     

Tranching and Rating

In this paper we analyse the source and magnitude of marketing gains from selling structured debt securities at yields that reflect only their credit ratings, or specifically at yields on equivalently rated corporate bonds. We distinguish between credit ratings that are based on probabilities of default and ratings that are based on expected default losses. We show that subdividing a bond issued against given collateral into subordinated tranches can yield significant profits under the hypothesised pricing system. Increasing the systematic risk or reducing the total risk of the bond collateral increases the profits further. The marketing gain is generally increasing in the number of tranches and decreasing in the rating of the lowest rated tranche.     

Moody's and S&P Ratings: Are They Equivalent? Conservative Ratings and Split Rated Bond Yields

We examine the relative impact of Moody's and S&P ratings on bond yields and find that at issuance, yields on split rated bonds with superior Moody's ratings are about 8 basis points lower than yields on split rated bonds with superior S&P ratings. This suggests that investors differentiate between the two ratings and assign more weight to the ratings from Moody’s, the more conservative rating agency. Moody's becomes more conservative after 1998 and the impact of a superior Moody's rating becomes stronger. Furthermore, the differential impact of the two ratings is more pronounced for the more opaque Rule 144A issues.     

Why Gaussian macro-finance term structure models are (nearly) unconstrained factor-VARs

This paper explores the implications of filtering and no-arbitrage for the maximum likelihood estimates of the entire conditional distribution of the risk factors and bond yields in Gaussian macro-finance term structure model (MTSM) when all yields are priced imperfectly. For typical yield curves and macro-variables studied in this literature, the estimated joint distribution within a canonical MTSM is nearly identical to the estimate from an economic-model-free factor vector-autoregression (factor-VAR), even when measurement errors are large. It follows that a canonical MTSM offers no new insights into economic questions regarding the historical distribution of the macro risk factors and yields, over and above what is learned from a factor-VAR. These results are rotation-invariant and, therefore, apply to many of the specifications in the literature.     

Benchmarking Australian fixed interest fund performance: finding the optimal factors

In this paper, we analyse the performance of Australian fixed interest managed funds and assess multiple benchmarks through which such performance can be reliably measured. We examine the effectiveness of seven indices of bond performance, as well as factors impacting on fixed interest asset values and, hence, returns, including interest rate fluctuations, economic fundamentals, maturity risk, default risk and cross‐market influences. We test all combinations of factors in cross‐section and time series to find the optimum benchmark. The results, consistent across time, show that a correct combination of a fund‐based market variable, a mixture of interest rate factors and economic factors as well as a proxy for movements in the equity markets yield the optimal benchmark.     

银行间债市收益率上扬的成因及后市展望

自2013年6月以来,利率的上行趋势已从货币市场利率扩散到中长端国债收益率,并蔓延到短端收益率。回归分析结果表明,经济基本面和资金面仅可部分解释国债收益率的上涨。文章进一步分析指出,货币政策维持中性偏紧趋向、金融机构调整资产配置结构削减债券投资额度、银行筹资方式多元化推高资金成本这三大因素,也是引起本轮利率接力上行的显著外力。中长期看,债券市场收益率中枢将随之抬升。在中性偏紧的货币政策基调没有改变前,债券市场将只有阶段性回嗳而无趋势性好转的行情。