THE IMPACT OF SPLIT BOND RATINGS ON RISK PREMIA

Interest rates for bonds are negatively correlated with credit ratings assigned by agencies such as Moody's Investor Service and Standard & Poor's. Still in dispute is whether or not the ratings themselves convey information that is reflected in prices, hence interest rates in the bond markets. Disagreement between these two agencies' ratings leads to “split” ratings, and in this paper, the authors use the phenomenon of split ratings to assess whether or not ratings have a separate impact on bond prices. The results indicate that a downside split appears to have greater bond yield impact than an upside split. The findings are inconsistent with bond market efficiency, at least in the strong form. The market considers the quality of a split-rated bond to reflect the lower of the two ratings. Finally, the symmetry of the results with respect to the ratings agencies indicates that neither agency has more influence than the other in determining bond yields.     

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.     

Split bond ratings and rating migration

This paper examines the relationships between split ratings and ratings migration. We find that bonds with split ratings are more likely to have future rating changes. A one-notch (more-than-one-notch) split rating increases the probability of rating change within one year of initial issuance by about 3% (6%). Furthermore, we find that about 30% of split rated bonds have their two ratings converge after four years of initial issuance. The rating convergence tapers off after three years, and the rating agency with a higher (lower) initial rating generally maintains a higher (lower) rating in subsequent years if the two ratings do not converge. We also show that rating transition estimation can be improved by taking into consideration split ratings. We find that one-year rating transition matrices are significantly different between non-letter-split rated bonds and letter-split rated bonds, and we show that the difference has an economically significant impact on the pricing of credit spread options and VaR-based risk management models. Overall, our results suggest that split ratings contain important information about subsequent rating changes.     

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.     

INFORMATION OPACITY AND FITCH BOND RATINGS

We examine the marginal impact of Fitch ratings on the at‐issuance yields of industrial and utility bonds rated by Moody's and Standard & Poor's. We find that Fitch ratings reduce the yield premiums on information‐opaque bonds by about 30%, or 15 basis points. The finding is robust even when a Fitch rating exactly equals the two major ratings or their average. The findings suggest that Fitch ratings are not redundant but bring additional information to investors. Increased competition in the rating industry enhances the information efficiency of the bond market, and the existence of smaller rating agencies is economically justified.     

Dual Bond Ratings: A Test of the Certification Function of Rating Agencies

Bond researchers have recently observed that issues with split ratings have yields more closely resembling the yields on bonds with the lower of the two ratings. This evidence could lead researchers to question why an issuer ever obtains more than one rating in an environment where two ratings, when split, can never reduce yields, whereas two ratings, when split, can increase yields. This paper explores the rating function in a certification framework and concludes that investors value a second rating. Bond issues with two identical ratings have yields significantly less than issues receiving that rating from only one rating agency.     

Do bond credit ratings lead to excess comovement?

We investigate whether non-fundamental comovement results from investors using credit ratings to group assets into different “styles”. We find that bonds that join a new rating class start comoving more with the bonds in this class, even when fundamental factors suggest otherwise. We show that this comovement effect varies according to the nature of the bond considered, and the modalities of the rating action. Downgrades have a larger impact than upgrades, and rating reviews matter as much as actual movements. Finally, rating changes between grades BBB and BB, which lead bonds to be reclassified as either “high-yield” or “investment grade” assets, seem to be of particular importance.     

Rating Agency Reputation,the Global Financial Crisis,and the Cost of Debt

Why do foreign firms obtain credit ratings by global rating agencies rather than from their home country's rating agencies even though global raters typically assign lower credit ratings when these foreign firms issue bonds in their home currencies? We find that bonds rated by a global agency decreased yields 11‐14 basis points (bps) when compared to those rated by Japanese rating agencies but, during the 2007‐2009 financial crisis, the yields on these Japanese bonds increased 12‐17 bps, thus fully negating the advantage of obtaining a bond rating from a global rater. This suggests that the reputation of global rating agencies declined during the 2007‐2009 crisis period.     

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.     

Underwriter reputation and the quality of certification: Evidence from high-yield bonds

This paper provides primary evidence of whether certification via reputable underwriters is beneficial to investors in the corporate bond market. We focus on the high-yield bond market in which certification of issuer quality is most valuable to investors owing to low liquidity and issuing firms’ high opacity and default risk. We find bonds underwritten by the most reputable underwriters to be associated with significantly higher downgrade and default risk. Investors seem to be aware of this relation, as we further find the private information conveyed via the issuer-reputable underwriter match to have a significantly positive effect on at-issue yield spreads. Our results are consistent with the market-power hypothesis, and contradict the traditional certification hypothesis and underlying reputation mechanism.     

Unsolicited Versus Solicited: Credit Ratings and Bond Yields

This paper is the first attempt to analyze Standard & Poor’s unsolicited and solicited ratings by using bond-yield data in Japan. Our findings show that there are differences in firm characteristics between firms seeking solicited ratings and those that receive unsolicited ratings. Firms with solicited ratings have less information asymmetry and are more likely to be owned by foreign investors, generate more revenue from exports, be cross-listed in the US, and have higher firm quality. But, firms with unsolicited ratings pay higher costs for debt, and their bond prices react more strongly to credit-rating changes. Yield spreads for new bonds with unsolicited ratings are higher than those with solicited ratings, because unsolicited ratings have higher information asymmetry, and investors therefore demand higher yields. We find that bond-price reactions to the announcements of unsolicited rating downgrades (upgrades) are negative (positive) and significant, while bond prices do not react significantly to solicited rating downgrades or upgrades.     

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.     

Ratings Quality and Borrowing Choice

Past studies document that incentive conflicts may lead issuer‐paid credit rating agencies to provide optimistically biased ratings. In this paper, we present evidence that investors question the quality of issuer‐paid ratings and raise corporate bond yields where the issuer‐paid rating is more positive than benchmark investor‐paid ratings. We also find that some firms with favorable issuer‐paid ratings substitute public bonds with borrowings from informed intermediaries to mitigate the “lemons discount” associated with poor quality ratings. Overall, our results suggest that the quality of issuer‐paid ratings has significant effects on borrowing costs and the choice of debt.     

A Comparison of Bond Ratings from Moody's S&P and Fitch IBCA

Previous research has found that the bond market values the ratings of Moody's and Standard & Poor's. This paper extends earlier research by comparing the ratings of Moody's, Standard and Poor's, and Fitch IBCA. The authors examine a very large database with monthly observations of bonds and bond ratings over a five‐year time period. The analysis focuses on comparing rating levels, rating changes, and the impact of ratings on bond yields. The results show that firms with publicly available Fitch IBCA ratings have higher ratings from Moody's and S&P than firms without Fitch IBCA ratings. The typical firm releasing a Fitch IBCA rating has a lower yield (controlling for Moody's and S&P rating), a more stable rating, and is more likely to receive an upgrade. For split‐rated bonds (Moody's vs. S&P), Fitch IBCA serves as a tiebreaker. This evidence is consistent with the bond market valuing the ratings of all three raters—Moody's, Standard & Poor's, and Fitch IBCA.     

Does it matter who pays for bond ratings? Historical evidence

We test whether Standard and Poor's (S&P) assigns higher bond ratings after it switches from investor-pay to issuer-pay fees in 1974. Using Moody's rating for the same bond as a benchmark, we find that when S&P charges investors and Moody's charges issuers, S&P's ratings are lower than Moody's. Once S&P adopts issuer-pay, its ratings increase and no longer differ from Moody's. More importantly, S&P only assigns higher ratings for bonds that are subject to greater conflicts of interest, measured by higher expected rating fees or lower credit quality. These findings suggest that the issuer-pay model leads to higher ratings.     

私有信息、评级偏差和中国评级机构的市场声誉

考虑到评级机构拥有市场声誉的本质在于其可以通过扭曲评级从而对市场产生影响,本文分两步研究中国发行人付费评级机构的市场声誉:第一步,将信用评级对各种基本面因素进行回归,并以实际评级与回归预测值的差值作为评级偏差的量度。与既有文献相比,本文的重要改进是在基本面因素中引入了发债企业与各评级机构(分支机构)最短距离的均值和方差,这能较好地控制因发债企业私有信息可能造成的选择偏误。第二步,考察评级偏差和机构特征如何影响企业的发债成本。研究表明,中国评级机构作为一个整体具有显著的市场声誉,但各评级机构之间存在很大的差异性。最后,考虑到评级机构与发债企业在选址上可能会有集聚效应,我们基于高铁开通事件进行双重差分检验,研究表明本文结论是稳健的。     

AN EXAMINATION OF THE YIELD SPREAD BETWEEN INSURED AND UNINSURED DEBT

Currently, municipal bonds insured by major insurance firms receive the highest credit rating from rating agencies. The interest rates on regular triple-A municipal bonds, however, have been persistently below those of insured bond issues. The yield spread between insured and uninsured triple-A bonds in the tax-exempt market is examined here, and it is shown that the yield spread may be attributable to split ratings and default-related risks.     

Asset Opaqueness and Split Bond Ratings

We examine the relation between asset opaqueness and split ratings. We find that firms with asset opaqueness problems are more likely to receive split bond ratings from Moody s and S&P rating agencies. Our results suggest that there is a causal link between asset opaqueness and split ratings.     

Cross‐Listed Bonds,Information Asymmetry,and Conservatism in Credit Ratings

We propose information asymmetry as an additional explanation for rating conservatism. Because information asymmetry is likely higher for cross‐listed bonds than for U.S. bonds, we expect and find that cross‐listed bonds are rated more conservatively than U.S. domestic bonds at issuance. Further, cross‐listed bonds receive less frequent upgrades and take longer to be upgraded after issuance. Because lower ratings might also reflect higher default risk based on agencies’ private information, we conduct additional tests to discriminate between the rating conservatism and private information explanations. The results are consistent with ratings conservatism and inconsistent with the private information explanation.     

The Riskiness of Corporate Bonds

We use an index of riskiness recently proposed by Aumann and Serrano ( 2008 ) to analyze how the riskiness of diversified portfolios of corporate bonds changes across rating classes and through time and how it compares to the riskiness of other financial instruments. We find that differences in riskiness among portfolios of bonds belonging to different rating classes are seldom statistically significant. We instead find significant time variation in riskiness, driven mainly by return volatility, inflation, and average bond yields. In particular, we find that increases in average bond yields have historically tended to reduce the riskiness of portfolios of corporate bonds by increasing their expected return and by lowering the probability of portfolio losses.