Modelling sovereign credit ratings: The accuracy of models in a heterogeneous sample

The accuracy of sovereign credit ratings renewed interest toward sovereign credit ratings in the aftermath of the 2008 financial crisis. The controversy over the accuracies encouraged internal credit scoring systems to reduce reliance on sovereign credit ratings. By employing classification and regression trees (CART), multilayer perceptron (MLP), support vector machines (SVM), Bayes Net, and Naïve Bayes; we explore the prediction performance of several artificial intelligence (AI) techniques in predicting sovereign credit ratings in a heterogeneous sample. The results suggest that AI classifiers outperform the conventional statistical technique in terms of accurate prediction. According to within one notch and two notches accurate prediction measure, the prediction performances of the AI classifiers exceed 90% accuracy whereas the performance of the conventional statistical method is around 70%. The results further reveal that the prediction performance of the models declines around the threshold rating that is located between investment grade and speculative grade which is not necessarily the result of inadequacy of the models. Rather, this is potentially due to CRAs' cautious behaviour toward those countries around threshold rating which can be interpreted as the certification price of upgrading to investment grade.     

PIGS or Lambs? The European Sovereign Debt Crisis and the Role of Rating Agencies

This paper asks whether rating agencies played a passive role or were an active driving force during Europe??s sovereign debt crisis. We address this by estimating relationships between sovereign debt ratings and macroeconomic and structural variables. We then use these equations to decompose actual ratings into systematic and arbitrary components that are not explained by previously observed procedures of rating agencies. Finally, we check whether systematic, as well as arbitrary, parts of credit ratings affect credit spreads. We find that both do affect credit spreads, which opens the possibility that arbitrary rating downgrades trigger processes of self-fulfilling prophecies that may drive even relatively healthy countries towards default.     

Sovereign credit ratings in the European Union: A model-based fiscal analysis

We present a model-based measure of sovereign credit ratings derived solely from the fiscal position of a country: a forecast of its future debt liabilities, and its potential to use fiscal policy to repay these. We use this measure to calculate credit ratings for 14 European countries over the period 1995–2012. This measure identifies a European sovereign debt crisis almost two years before the official ratings of the credit rating agencies.     

Bank Credit Risk Management and Migration Analysis; Conditioning Transition Matrices on the Stage of the Business Cycle

Credit risk has been one of the most active areas of recent financial research. It is driven by advances in portfolio risk measurement and management techniques, growth in credit derivatives trading, the Basel II implementation, and regulatory concerns stemming from the commercial credit crunch that initially took place in 2001 and 2002 in the USA. Within this broader literature, a growing body of research analyzes the meaning, role, and influence of credit ratings that quantify credit risk. This paper examines the two-way links between credit risk measurement and the macroeconomic conditions, interpreted through phases of business cycles. We propose a methodology applied on bank internal rating data, which estimates ratings migration probabilities while integrating the state of the economy. We first discuss the issue of whether credit risk is low or high in different economic scenarios. In order to evaluate this prospect, we examine each year in four quarters that represent different scenarios throughout the year. We then review how macroeconomic considerations are incorporated into credit risk models and the risk measurement approach that underlies Basel II and Basel III.     

国家主权信用评级、跨国传染与股票市场回应?--基于全球48个经济体的事件研究

掌握主权信用评级变动的市场影响及其传染机制,对于投资者、国家金融安全及政府采取应对措施来说都意义重大。文章采用事件研究法,以1990-2013年全球48个经济体发生的评级事件和每日股指收益率数据为样本,实证研究了事件国评级变动对非事件国股票市场的影响及其传染渠道,结果表明：(1)评级下调会对股票市场产生显著为负的超额收益,但评级上调产生的超额收益不显著;(2)股票市场可以提前预测评级下调事件,但不能预测评级上调事件;(3)季风效应对评级调整的市场传染有一定的解释力;(4)净传染效应基本不显著,这说明评级事件的市场传染应该有经济基础,而不是由投资者心理预期这类非基本面因素造成的;(5)溢出效应可以较好地解释评级的市场传染,是评级变动影响市场及传染的主要渠道。文章的结论深化了我们对评级调整如何影响股票市场及其传染渠道的认识,也为中国防范国外主权信用评级变动风险提供了有益启示。     

Credit ratings and bond spreads of the GIIPS

We examine the relationship between credit ratings and bond yield spreads of peripheral countries in the euro area (Greece, Ireland, Italy, Portugal and Spain) for the period 1995–2014. Since 2012, bond spreads of those countries have come down very fast, whereas credit ratings have hardly changed. Our results suggest that credit rating agencies have become more cautious and have changed their approach to assess credit risk of sovereigns, and that the impact of sovereign credit risk ratings on sovereign bond spreads has changed.     

Emerging market sovereign bond spreads,credit ratings and global financial crisis

This paper investigates the impacts of sovereign credit ratings and global financial conditions on the evolution of EMBI Global (EMBIG) spreads for a panel of 23 developing countries by using daily data for the period between 1998 and 2012. To this end, we employ not only the conventional panel estimation procedures, but also the recent methods tackling with either cross-sectional dependence stemming from common global shocks or a potential endogeneity. Our results suggest that credit ratings along with global financial conditions re the main determinants of EMBIG spreads. The determinants of EMBIG spreads are not invariant to speculative and investment grade episodes and transitions between them. The recent global crisis changed the determinants of EMBIG spreads and led to credit ratings' impact to converge between speculative and investment grade countries.     

Does income inequality really matter for credit booms?

This paper addresses the question whether income inequality is associated with credit booms, alongside other macroeconomic factors. We distinguish between the different types of credit booms—real estate credit booms, household credit booms, firm credit booms and credit booms that turn into crises. Furthermore, our analysis of a sample of 70 countries between 1990 and 2016 does not provide any evidence of credit booms driving income inequality. We observe that capital inflows increase the likelihood of credit boom occurrence, while countries experiencing high economic growth tend to have more credit booms. Finally, we note that credit booms are more frequent in countries with fixed exchange rate regimes.     

Rating Agency Actions and the Pricing of Debt and Equity of European Banks: What Can we Infer About Private Sector Monitoring of Bank Soundness?

The recent consultative papers by the Basel Committee on Banking Supervision has raised the possibility of an explicit role for external rating agencies in the assessment of the credit risk of banks' assets, including interbank claims. Any judgement on the merits of this proposal calls for an assessment of the information contained in credit ratings and its relationship to other publicly available information on the financial health of banks and borrowers. We assess this issue via an event study of rating change announcements by leading international rating agencies, focusing on rating changes for European banks for which data on bond and equity prices are available. We find little evidence of announcement effects on bond prices, which may reflect the lack of liquidity in bond markets in Europe during much of our sample period. For equity prices, we find strong effects of ratings changes, although some of our results may suffer from contamination by contemporaneous news events. We also test for pre-announcement and post-announcement effects, but find little evidence of either. Overall, our results suggest that ratings agencies may perform a useful role in summarizing and obtaining non-public information on banks and that monitoring of banks' risk through bond holders appears to be relatively limited in Europe. The relatively weak monitoring by bondholders casts some doubt on the effectiveness of a subordinated debt requirement as a supervisory tool in the European context, at least until bond markets are more developed.
(J.E.L.: E53, G21, G33)     

Estimation of conditional time-homogeneous credit quality transition matrices

This paper presents a methodology for estimating time-homogeneous credit quality transition matrices. Using a unique data set on credit ratings of commercial loans in Colombia, we show that 70% of the time we cannot reject the null hypothesis of time homogeneity of transition matrices estimated this way. We also find that obtaining matrices for different subsamples is not necessary, given the similarities of the survival functions.     

The democratic (dis)advantage: The conditional impact of democracy on credit risk and sovereign default

Many have argued that democracies are able to make credible commitments to repay their debts and consequently enjoy higher sovereign credit ratings. In contrast to this expectation, I argue that the advantage of democracies in credit ratings is conditional on the countries' level of financial vulnerability and adjustment needs. Because democracies have more diffuse decision-making and are more accountable to the public, they encounter greater difficulty than autocracies in passing unpopular economic adjustment measures. Thus, I argue that democracies with high debt levels and low foreign reserve assets experience worse credit outcomes, whereas democracies with low vulnerability experience more positive outcomes. In a sample of up to 96 developing countries, I show that democracies have worse credit ratings and CDS Spreads and are more likely to default than their autocratic counterparts when foreign reserves are low relative to external debt. Notably, I also show that large debt burdens increase credit risk mainly in more democratic countries. I further test the causal pathway of the democratic advantage by constructing democracy scores of “market-friendly” and “adjustment-difficulty” democracy, finding that democracy worsens debt outcomes due to adjustment difficulty. These findings help to revise and clarify the causal logic surrounding the democratic advantage hypothesis.     

Exploring the mismatch between credit ratings and loss-given-default: A credit risk approach

It is commonly observed that high grade loans with better ratings are often associated with low recoveries if they default (i.e. with relatively high loss-given-default (LGD)). To address the mismatch problem, this paper proposes a credit risk approach by minimizing LGD for higher rated loans as a risk-rating matching standard in the sense that the decreasing LGD from creditors’ perspective is associated with higher credit rating for the borrower. This standard forces customers’ credit rating of each grade to be optimally determined in correspondence to its LGD, which means the LGD of high grade loans tends to be low. The approach is then tested using three credit datasets from China, i.e. credit data from 2044 farmers, 2157 small private businesses and 3111 SMEs. The empirical results show that the proposed approach indeed guides the way to solve the mismatch phenomenon between credit ratings and LGDs in the existing credit rating literature. By optimally determining credit ratings, the findings derived from this paper help provide a valuable reference for bankers, and bond investors to manage their credit risk.     

Forecasting Turkey’s Credit Ratings with Multivariate Grey Model and Grey Relational Analysis

The concept of credit rating rooted back to mid-nineteenth century has become one of the most important elements in the world economy together with the globalization period gradually accelerating in the last two decades and increasing the interaction and sensitivity in the international markets. With the globalization and deepening in the financial markets; the effect, reliability and stability of knowledge of the actors who are in charge for directing the global capital flows have quite a big importance in terms of the decisions to be made in the future. In this process, credit rating agencies eliminating the information asymmetry between the countries and institutions who want to create financial resource by borrowing from the savings owners and foreign institutions. Credit ratings determined by the mentioned organizations are accepted as an indicator of the countries to meet the financial obligations in other words their creditworthiness. For Turkey’s economy having a structure with a high level of external financing needs in terms of accelerating the growth and development process, it is inevitable to have an international creditworthiness increasing long-term investment tendency meeting foreign capitals’ trust search. In this study, firstly the determinants of the credit ratings given by credit rating agencies are determined and then forecasting Turkey’s future credit ratings by combining them with multivariate grey model and grey relational analysis are performed.

     

CREDIT RATING AND DEBT CRISES

We develop an equilibrium theory of credit rating in the presence of rollover risk. By influencing rational creditors, ratings affect sovereigns' probability of default, which in turn affects ratings. Our analysis reveals a pro‐cyclical impact of credit rating: In equilibrium the presence of a rating agency increases default risk when it is high and decreases default risk when it is low.     

信贷量经济效应的期限结构研究

银行信贷和经济波动的关系一直是理论和实务界关注的焦点,过去国内的研究大多仅从信贷总量层面入手而忽视了结构效应,这不利于厘清信贷在经济中的作用机理。在将贷款按期限划分为短期贷款和中长期贷款后,本文通过应用一个小型DSGE模型,发现短期贷款对经济增长虽有短期的促进作用,但却形成通货膨胀压力;而中长期贷款对经济增长有长期的促进作用,同时对通货膨胀有一定的抑制作用。以我国1998-2010年的宏观数据为样本进行的FAVAR检验支持了上述观点。该结论一方面意味着信贷政策及其监管应加强对信贷期限结构的关注,另一方面结合我国近年来中长期贷款比重大幅上升的客观事实,也从一个新的视角解释了货币信贷加速扩张的同时,价格水平却较为稳定的"中国货币之谜"。     

Are the credit ratings assigned by bankers based on the willingness of LDC borrowers to repay?

This paper examines whether the credit ratings assigned by the lenders can be explained using a set of explanatory variables selected from the willingness of LDC borrowers to repay their debt service obligations. The results indicate that first, the credit ratings provide a reasonable measure of borrower's creditworthiness and second, the set of the explanatory variables included in the study is significant in explaining variations in the credit ratings. Furthermore, inclusion of dummy variables for geographical location of borrowers, degree of indebtedness, and absolute size of debt suggests that there may be a significant group contagion in assigning credit ratings.     

Do employee dimension ratings reflect employee performance? Evidence from MSCI’s ESG database

We investigate whether the ratings of employee dimension in MSCI’s ESG database reflect employee performance of a firm. Using a large panel sample with 23,739 observations from 1991 to 2015, we find a significant positive relation between employee performance and employee dimension ratings. To mitigate concerns about endogeneity issues and robustness of our study, we perform various additional tests and still obtain consistent results. Overall, our findings suggest that the employee dimension ratings in MSCI’s ESG database accurately reflect employee performance.     

Credit card debt and consumption: evidence from household-level data

This research investigates the relationship between credit card debt and consumption using household level data. This is a departure from the previous studies which have used aggregate measures of consumption and general debt such as the Debt Service Ratio or total revolving credit. We use a detailed monthly survey of credit card use to impute credit card debt to respondents from the Consumer Expenditure Survey sample. In contrast to some earlier studies using aggregate data, we find a negative relationship between debt and consumption growth. Our work shows that a $1000 increase in credit card debt results in a decrease in quarterly consumption growth of almost 2%. Investigations are also made into effects of debt within different age categories and into the impact of expected income growth on the debt–consumption relationship.     

Does access to credit improve productivity? Evidence from Bulgaria1

Although it is widely accepted that financial development is associated with higher growth, the evidence on the channels through which credit affects growth at the microeconomic level is scant. Using data from a cross‐section of Bulgarian firms, we estimate the impact of access to credit, as proxied by indicators of whether firms have access to a credit line or overdraft facility, on productivity. To overcome potential omitted variable bias of Ordinary Least Squares (OLS) estimates, we use information on firms’ past growth to instrument for access to credit. We find credit to be positively and strongly associated with TFP. These results are robust to a wide range of robustness checks.     

The Impact of the Rating Agencies' Through‐the‐cycle Methodology on Rating Dynamics

Surveys on the use of agency credit ratings reveal that some investors believe that credit‐rating agencies are relatively slow in adjusting their ratings. A well‐accepted explanation for this perception on rating timeliness is the through‐the‐cycle methodology that agencies use. Through‐the‐cycle ratings are intended to measure default risk over long investment horizons and to respond only to changes in the permanent component of credit quality. A second aspect of the through‐the‐cycle methodology is the prudent migration policy. In a benchmark study with a financial ratio‐based credit‐scoring models – an agency‐rating prediction model and default‐prediction models with various time horizons – we confirm the exclusive focus of agencies on the permanent component of credit quality and we model and quantify the agencies' prudent migration policy. A rating migration is triggered only when the rating predicted by the agency‐rating prediction model differs by at least a threshold level of 1.8 notch steps from the actual agency rating. If triggered, ratings are only partly adjusted by 70 per cent at the downside and 60 per cent at the upside. From a 1‐year point‐in‐time perspective, weighting temporary fluctuations in credit quality, the through‐the‐cycle methodology lowers the rating‐migration probability by a factor of 3.5. Both aspects of the through‐the‐cycle methodology contribute equally to this factor. The partial adjustment of ratings lowers the rating‐reversal probabilities on short term and introduces rating drift, the known serial correlation in agency‐rating migrations.