Sovereign ceilings “lite”? The impact of sovereign ratings on corporate ratings

Although credit rating agencies have gradually moved away from a policy of never rating a corporation above the sovereign (the ‘sovereign ceiling’), it appears that sovereign credit ratings remain a significant determinant of corporate credit ratings. We examine this link using data for advanced and emerging economies over the period of 1995–2009. Our main result is that a sovereign ceiling continues to affect the rating of corporations. The results also suggest that the influence of a sovereign ceiling on corporate ratings remains particularly significant in countries where capital account restrictions are still in place and with high political risk.     

Credit rating dynamics in the presence of unknown structural breaks

In many credit risk and pricing applications, credit transition matrix is modeled by a constant transition probability or generator matrix for Markov processes. Based on empirical evidence, we model rating transition processes as piecewise homogeneous Markov chains with unobserved structural breaks. The proposed model provides explicit formulas for the posterior distribution of the time-varying rating transition generator matrices, the probability of structural break at each period and prediction of transition matrices in the presence of possible structural breaks. Estimating the model by credit rating history, we show that the structural break in rating transitions can be captured by the proposed model. We also show that structural breaks in rating dynamics are different for different industries. We then compare the prediction performance of the proposed and time-homogeneous Markov chain models.     

The impact of credit rating announcements on credit default swap spreads

We document the ability of the credit default swap (CDS) market to anticipate favorable as well as unfavorable credit rating change (RC) announcements based on more extensive samples of credit rating events and CDS spreads than previous studies. We obtain four new results. In contrast to prior published studies, we find that corporate RC upgrades do have a significant impact on CDS spreads even though they are still not as well anticipated as downgrades. Second, CreditWatch (CW) and Outlook (OL) announcements, after controlling for prior credit rating events, lead to significant CARs at the time positive CW and OL credit rating events are announced. Third, we extend prior results by showing that changes in CDS spreads for non-investment-grade credits contain information useful for estimating the probability of negative credit rating events. Fourth, we find that the CDS spread impact of upgrades but not downgrades is magnified during recessions and that upgrades and downgrades also differ as to the impact of simultaneous CW/OL announcements, investment-grade/speculative-grade crossovers, current credit rating, market volatility, and industry effects.     

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.     

Variations in sovereign credit quality assessments across rating agencies

We investigate agency variation in credit quality assessment (Standard and Poor’s vs. Moody’s vs. Fitch) employing sovereign ratings data for 129 countries, spanning the period 1990–2006. While we find that the credit rating agencies often disagree about credit quality, it is usually confined to one or two notches on the finer scale. We find that several variables have varying importance in explaining ratings across agencies which leads us to conclude that material heterogeneity exists between them. Also, while watch and outlook procedures are generally strong predictors of rating changes relative to other public data, additional significant variables suggest that it might be possible to augment these agency data to provide better forecasts of future rating changes.     

ARE WATCH PROCEDURES A CRITICAL INFORMATIONAL EVENT IN THE CREDIT RATINGS PROCESS? AN EMPIRICAL INVESTIGATION

The Boot, Milbourn, and Schmeits (2006) model (Boot model) predicts certain credit rating events are likely to be more informative than others and that credit watch procedures are an important driver of such differences. We test the core empirical predictions of their model. Our sample comprises U.S. corporate issuer credit ratings provided by Moody's, 1990–2006. Our findings fail to uncover compelling evidence for the empirical predictions of the Boot model in relation to the role of watch procedures as coordinating mechanisms. Rather, our findings are more supportive of the view that rating agencies are always at an informational advantage relative to investors.     

Credit rating dynamics and Markov mixture models

Despite mounting evidence to the contrary, credit migration matrices, used in many credit risk and pricing applications, are typically assumed to be generated by a simple Markov process. Based on empirical evidence, we propose a parsimonious model that is a mixture of (two) Markov chains, where the mixing is on the speed of movement among credit ratings. We estimate this model using credit rating histories and show that the mixture model statistically dominates the simple Markov model and that the differences between two models can be economically meaningful. The non-Markov property of our model implies that the future distribution of a firm’s ratings depends not only on its current rating but also on its past rating history. Indeed we find that two firms with identical current credit ratings can have substantially different transition probability vectors. We also find that conditioning on the state of the business cycle or industry group does not remove the heterogeneity with respect to the rate of movement. We go on to compare the performance of mixture and Markov chain using out-of-sample predictions.     

Securitization,risk-transferring and financial instability: The case of Spain

The 2007–2010 financial crisis has hit a variety of countries asymmetrically. The case of Spain is particularly illustrative as it exemplifies in a vivid manner most of the core issues largely responsible for the crisis. This country experienced a pronounced housing bubble partly funded via spectacular developments in its securitization markets leading to looser credit standards and subsequent financial stability problems. We analyze the sequential deterioration of credit in Spain considering rating changes in securitized deals. Using a sample of 20,286 observations on securities and rating changes from 2000Q1 to 2010Q1 we build a model in which loan growth, on balance-sheet credit quality and rating changes are estimated simultaneously. Our results suggest that loan growth significantly affects on balance-sheet loan performance with a lag of at least two years. Additionally, loan performance is found to explain rating changes with a lag of four quarters. Importantly, bank characteristics (in particular, observed solvency, cash-flow generation and cost efficiency) also affect ratings considerably. Additionally, these other bank characteristics seem to a higher weight in the rating changes of securities issued by savings banks as compared with commercial banks.     

Managerial ability and bond rating changes

This study examines the relation between managerial ability and bond credit rating changes. We attempt to add to the credit rating agency literature by exploring the role managerial ability plays in the initial bond rating assignments and in rating changes. We predict firms with more‐able managers are more likely to have higher bond ratings and to be more able to have a positive influence on rating changes. We find a significant and positive relation between managerial ability and change in credit ratings, suggesting that more‐able managers can take effective actions to improve their credit ratings.     

The sovereign-bank rating channel and rating agencies' downgrades during the European debt crisis

We investigate the rating channel for the transmission of changes in sovereign risk to the banking sector, analysing data from Moody's, S&P and Fitch before and during the European debt crisis. Sovereign rating downgrades and negative watch signals have strong effects on bank rating downgrades in the crisis period. The impact is stronger for multiple-notch sovereign rating downgrades, and more pronounced in PIIGS countries. Secondly, we investigate rating agencies' competition in the banking sector during the same periods, finding significant differences in rating policies across the agencies. S&P credit actions tend to be the more independent ones, while Moody's appears to be more cautious, although it is by far the most likely to assign multiple-notch downgrades. In the pre-crisis period, we find no evidence that bank rating actions are linked to sovereign rating signals (nor vice versa) nor to prior bank rating changes by a competing agency.     

The reaction of emerging market credit default swap spreads to sovereign credit rating changes

This paper examines the effect of sovereign credit rating change announcements on the CDS spreads of the event countries, and their spillover effects on other emerging economies’ CDS premiums. We find that positive events have a greater impact on CDS markets in the two-day period surrounding the event, and are more likely to spill over to other emerging countries. Alternatively, CDS markets anticipate negative events, and previous changes in CDS premiums can be used to estimate the probability of a negative credit event. The transmission mechanisms for positive events are the common creditor and competition in trade markets.     

Differences of opinion in sovereign credit signals during the European crisis

Motivated by the European debt crisis and the new European Union regulatory regime for the credit rating industry, we analyse differences of opinion in sovereign credit signals and their influence on European stock markets. Rating disagreements have a significant connection with subsequent negative credit actions by each agency. However, links among Moody’s/Fitch actions and their rating disagreements with other agencies have weakened in the post-regulation period. We also find that only S&P’s negative credit signals affect the own-country stock market and spill over to other European markets, but this is concentrated in the pre-regulation period. Stronger stock market reactions occur when S&P has already assigned a lower rating than Moody’s/Fitch prior to taking a further negative action.     

The optimal structure of PD buckets

In designing credit rating systems under the new Basel Accord, considerable effort has been devoted to rating assignment and quantification, while the choice of the optimal bucket structure has received less attention. To fill this gap, we propose two “bucketing” strategies based on constrained optimisation, paying attention to the implications of rating buckets for loan-pricing and adverse selection phenomena. We compare them with some more naïve approaches, based on a sample of about 100,000 European companies. We also analyse the persistence of our performance measures over time, as well as the effect of large exposures being associated with low-PD obligors.     

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.     

Compensation incentives of credit rating agencies and predictability of changes in bond ratings and financial strength ratings

Over the past decade there has been mixed evidence on the lead–lag relation between issuer-paid and investor-paid credit rating agencies. We investigate the lead–lag relationship for changes in bond ratings (BRs) and financial strength ratings (FSRs), for the US insurance industry, where FSRs impose market discipline. First, we find that changes in issuer-paid BRs are led by changes in investor-paid BRs, even over a period that issuer-paid agencies have improved their timeliness. Second, information flows in both directions between changes in issuer-paid BRs and FSRs. Third, issuer-paid FSRs are predictable by investor-paid BRs. Fourth, the lead effect of investor-paid downgrades is economically significant as it is associated with an unconditional, post-event, 30-day cumulative abnormal return of −4%. This return is a result of investor-paid downgrades in BRs, which predict more downgrades in the following 90 days (same period return of −11%).     

A comparative study of the probability of default for global financial firms

This article presents a modification of Merton’s (1976) ruin option pricing model to estimate the implied probability of default from stock and option market prices. To test the model, we analyze all global financial firms with traded options in the US and focus on the subprime mortgage crisis period. We compare the performance of the implied probability of default from our model to the expected default frequencies based on the Moody’s KMV model and agency credit ratings by constructing cumulative accuracy profiles (CAP) and the receiver operating characteristic (ROC). We find that the probability of default estimates from our model are equal or superior to other credit risk measures studied based on CAP and ROC. In particular, during the subprime crisis our model surpassed credit ratings and matched or exceeded KMV in anticipating the magnitude of the crisis. We have also found some initial evidence that adding off-balance-sheet derivatives exposure improves the performance of the KMV model.     

Regulation of credit rating agencies

Financial regulators recognize certain credit rating agencies for regulatory purposes. However, it is often argued that credit rating agencies have an incentive to assign inflated ratings. This paper studies a repeated principal-agent problem in which a regulator approves credit rating agencies. Credit rating agencies may collude to assign inflated ratings. Yet we show that there exists an approval scheme which induces credit rating agencies to assign correct ratings.     

The use of earnings and operations management to avoid credit rating downgrades

Firms placed on negative credit watch face the threat of a credit rating downgrade. At the same time, they are given the opportunity to put recovery efforts in place to retain their current credit rating. In this paper, we test to what extent firms use earnings management as a short-term recovery strategy. We find that both accruals-based and real earnings management are associated with firms avoiding credit rating downgrades, and that these alternative earnings management strategies tend to be complements rather than substitutes. However, following the passage of the Sarbanes–Oxley Act, only real earnings management is significantly associated with the credit watch outcome. We find evidence that firms which maintain their rating via earnings management are better able to afford the inevitable earnings reversals, and that in the year following the credit watch period, the credit rating performance of these firms is significantly better than firms which undergo a downgrade, with fewer downgrades and more upgrades in this period. Our results also imply that credit rating agencies are not misled by earnings management but rather allow for some discretion in reporting earnings that facilitates the dissemination of private information about future firm performance.     

Do banks price their informational monopoly?

Theory suggests that banks’ private information lets them hold up borrowers for higher interest rates. Since new information about a firm is revealed at the time of its bond IPO, it follows that banks will be forced to adjust their loan interest rates downwards after firms undertake their bond IPO. We test this hypothesis and find that firms are able to borrow at lower interest rates after their bond IPO. Importantly, firms that get their first credit rating at the time of their bond IPO benefit from larger interest rate savings than those that already had a credit rating. These findings provide support for the hypothesis that banks price their informational monopoly. We also find that it is costly for firms to enter the public bond market.     

Looking Beyond Credit Ratings: Factors Investors Consider In Pricing European Asset‐Backed Securities

In this paper, we empirically investigate what credit factors investors rely upon when pricing the spread at issue for European asset‐backed securities. More specifically, we investigate how credit factors affect new issuance spreads after taking into account credit rating. We do so by investigating primary market spreads for tranches of non‐mortgage‐related asset‐backed securities issued from 1999 to the year prior to the subprime mortgage crisis, 2007. We find that although credit ratings play a major role in determining spreads, investors appear to not rely exclusively on these ratings. Our findings strongly suggest that investors do not ignore other credit factors beyond the assigned credit rating.