主权信用评级的决定因素与信用评级机构的规范化研究

目前,国际信用评级机构遭遇了自其建立以来最严峻的信任危机。本文研究了主权信用评级的决定因素,并从近几次危机中评级失真的原因分析入手,提出了信用评级机构的规范化方法。研究表明:正常年份中,债务国发展的基本面情况是主权信用评级的主要决定因素;评级行业的垄断与评级机构特殊的政治目的固然是近年来评级失真频现的原因,但国际投资者对于评级机构的过度依赖亦是危机中"评级结果决定主权走势"现象出现的原因之一。要辩证地看待评级机构,既不能一概否认,也不能无限夸大,应该在提高投资者自身风险评估能力的基础上,强化评级市场的竞争,并且努力构建内外监管相结合的全方位监管体系。     

主权信用评级对国债发行成本的影响研究——兼议国际主权信用评级的合理性

自美国次贷危机爆发以来,国际三大评级机构的主权信用评级结果备受国际投资者的质疑。文章以中国和美国在2008年8月至2018年9月期间发行的固定利率附息国债为研究对象,通过建立真实利息成本模型来分析主权信用评级对中美两国国债发行成本的影响。实证检验结果表明,标普信用评级的变动并未对国债发行成本产生预期影响。进一步,文章结合2017年9月标普下调我国主权信用评级的案例,对现行国际主权信用评级体系的不合理性及破除主权信用评级霸权的重要性进行剖析,并提出提升我国在主权信用评级市场上话语权的政策建议。     

主权信用评级的决定因素与信用评级机构的规范化研究

目前,国际信用评级机构遭遇了自其建立以来最严峻的信任危机。本文在简要介绍信用评级机构与主权信用评级的基础上,从定性与定量的角度研究了主权信用评级的决定因素;并从近几次危机中评级失真的原因分析入手,提出了信用评级机构的规范化方法。研究表明:1、正常年份中,债务国发展的基本面情况是主权信用评级的主要决定因素;2、评级行业的垄断与评级机构特殊的政治目的固然是近年来评级失真频现的原因,但国际投资者对于评级机构的过度依赖亦是危机中"评级结果决定主权走势"现象出现的原因之一;3、我们要辩证地看待评级机构,既不能一概否认,也不能无限夸大,应该在提高投资者自身风险评估能力的基础上,强化评级市场的竞争,并且努力构建内外监管相结合全方位监管体系。     

国际三大评级机构主权信用评级模式的经验及启示

发展和完善主权信用评级业是维护我国金融主权和经济安全的重要举措. 以标准普尔、穆迪、惠誉三家评级机构为代表的国际评级机构,均通过综合评估政府偿还债务的能力和意愿来展示主权国家的信用状况. 此评级模式采用定量与定性结合的评估方式,评级指标全面、准确、完整,但具有潜意识下的制度偏好,易受主观影响且透明度不高. 借鉴国际经验,我国应大力扶持主权信用评级机构发展,建立自己的评级标准和模式,并加强主权信用评级市场的规范和监管.     

基于逆周期的主权信用评级指标体系构建

现行国际主权信用评级体系存在明显的顺周期效应,从技术上看主要是其评级指标体系的设计不合理,一方面反映一国历史经济实力和政治理念的指标较多,另一方面反映一国未来发展潜力、负债状况和偿债能力的指标较少,这就导致经济繁荣时评级被高估而经济衰退时评级被低估.为了解决指标重复和指标欠缺的问题,应该将经济发展水平变量指标剔除,将人均收入、实际经济增长率、通胀率、外债、违约历史变量等指标保留下来,同时将短期外债、外债还本付息额、财政余额、经常账户余额、出口增长率变量等指标加入新建指标体系.选择这10个指标来评估一国主权信用风险更为符合经济原理和客观现实.     

三大评级机构与大公国际主权信用评级模式比较

本文研究包括主权信用评级历史、三大机构和大公国际评级基本思想、影响因素、争议及动因。研究发现：分歧源于两个体系指导思想的不同,从而带来核心指标的差异,三大机构评级体系以一国经济形态、开放度和人均GDP为主要参考标准,而大公国际则回归债权债务人最原始定义,重点考虑一国的财富新创造能力,摒除过多制度考量。     

主权信用评级问题研究

主权信用评级在金融危机中发挥预警作用的同时,还在一定程度上起到了推波助澜的作用。随着各国政府在国际资本市场上发行主权债券的增多,主权信用评级从商业领域步入政治经济领域,不得不引起世界各国政府的高度关注。评级公司在对主权风险进行评级的过程中存在着很多问题,如道德风险、评级失误等,对主权评级过程、模型进行研究、修正具有十分重要的现实意义。本文对标普公司主权评级模型进行了介绍,对主权评级模型提出建议,并对美国主权信用登记进行了分析。     

主权信用评级的规则演变和实践

目前,主权信用封顶规则已被国家信用限额规则取代.从实践上看,三大评级机构在计量经济研究范式基础上所研发的评级模型仍将一国经济的私有化、自由化和对外开放程度以及与美日欧的关系作为判断经济结构和经济前景的主要依据,具有强烈的新自由主义和华盛顿共识色彩.为与国际接轨,中国本土信用评级机构需要推行国家信用限额规...     

基于逆周期的主权信用评级指标体系研究

现行国际主权信用评级呈现出明显的顺周期特征而广受诟病。在对评级指标体系优化的基础上,采用90个主权国家2005~2012年经济数据进行面板随机效应和门限效应回归,对主权信用评级决定模型进行估计,运用欧债危机发生前后的数据进行模拟评级,结果表明：优化后的指标体系显示出较好的逆周期特征。     

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.     

New evidence on sovereign to corporate credit rating spill-overs

We explore what happens to domestic firm-level ratings around the time of a sovereign-rating action on a day-by-day and country-by-country basis. Our granular approach provides banks and investors with a fuller picture of their sovereign credit risk exposure and, as such, our analysis might feed into banks' internal modelling of their credit risk exposure for the purpose of determining regulatory capital, introduced under Basel II. We also provide a novel analysis of any bias in spill-over and we show that, inter alia, the tendency for greater spill-over of negative sovereign-rating actions can largely be accounted for by firm- and sovereign-level factors. However, even after allowing for these factors, some countries suffer from negative bias. The implied higher correlation between sovereign and firm-level ratings in times when countries are in crisis versus when they are in recovery may contribute to quicker and/or deeper crises versus slower and/or longer recoveries.     

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.     

Economic policy uncertainty and sovereign credit rating decisions: Panel quantile evidence for the Eurozone

We employ a panel quantile framework that quantifies the relative importance of quantitative and qualitative factors across the conditional distribution of sovereign credit ratings in the Eurozone area. We find that regulatory quality and competitiveness have a stronger impact for low rated countries whereas GDP per capita is a major driver of high rated countries. A reduction in the current account deficit leads to a rating or outlook upgrade for low rated countries. Economic policy uncertainty impacts negatively on credit ratings across the conditional distribution; however, the impact is stronger for the lower rated countries. In other words, the creditworthiness of low rated countries takes a much bigger ‘hit’ than that of high rated countries when European policy uncertainty is on the rise.     

Sustainability and sovereign credit risk

The study investigates the impact of Environmental, Social, and Governance (ESG) ratings on sovereign credit risk. The study measures sovereign credit risk using a market-based, structural and an analyst-based approach, while ESG scores are obtained from three different rating agencies. The contributions of this paper are multifold. First, we discover that higher sustainability performance at the corporate level significantly decreases market-based (CDS spreads) and structural (Distance-to-default) sovereign credit risk but has no consistent impact on analyst-based (Credit ratings) sovereign credit risk measure. Second, by expanding our research to include the concept of financial materiality based on the SASB materiality map, we break down and highlight the sustainability themes that require the most attention at the sovereign level and those that can affect the credit health of countries. Third, we demonstrate that the relationship between sustainability and sovereign credit risk varies across ESG rating providers, supporting the widespread belief that sustainability metrics lack standardization and are difficult to compare across providers.     

News sentiment and sovereign credit risk

We explore the impact of media content on sovereign credit risk. Our measure of media tone is extracted from the Thomson Reuters News Analytics database. As a proxy for sovereign credit risk we consider credit default swap (CDS) spreads, which are decomposed into their risk premium and default risk components. We find that media tone explains and predicts CDS returns and is a mixture of noise and information. Its effect on risk premium induces a temporary change in investors’ appetite for credit risk exposure, whereas its impact on the default component leads to reassessments of the fundamentals of sovereign economies.     

Explaining credit rating differences between Japanese and U.S. agencies

We compare credit ratings assigned to Japanese firms by the two leading U.S. rating agencies and the two leading Japanese agencies. Our goal is to investigate the complaint that the U.S. agencies Moody's and Standard and Poor's (S&P) ignore special corporate governance features of Japanese firms, i.e., keiretsu affiliation. We find that it is true that ratings of Japanese firms by the U.S. agencies are systematically lower than those assigned by Japanese raters. However, the reasons for the differences are not found to be related to keiretsu affiliation. Thus, we reject one of the prominent reasons for rating differences put forth by managers of Japanese firms. This leaves open the question of what drives the difference. The phenomenon is clearly consistent with more general home bias documented in previous work.     

Leads and lags in sovereign credit ratings

This paper analyses lead–lag relationships in sovereign ratings across five agencies, and finds evidence of interdependence in rating actions. Upgrade (downgrade) probabilities are much higher, and downgrade (upgrade) probabilities are much lower for a sovereign issuer with a recent upgrade (downgrade) by another agency. S&P tends to demonstrate the least dependence on other agencies, and Moody’s tends to be the first mover in upgrades. Rating actions by Japanese agencies tend to lag those of the larger agencies, although there is some evidence that they lead Moody’s downgrades.     

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.     

Foreign exchange market reactions to sovereign credit news

We analyse the reaction of the foreign exchange spot market to sovereign credit signals by Fitch, Moody’s and S&P during 1994–2010. We find that positive and negative credit news affects both the own-country exchange rate and other countries’ exchange rates. We provide evidence on unequal responses to the three agencies’ signals. Fitch signals induce the most timely market responses, and the market also reacts strongly to S&P negative outlook signals. Credit outlook and watch actions and multiple notch rating changes have more impact than one-notch rating changes. Considerable differences in the market reactions to sovereign credit events are highlighted in emerging versus developed economies, and in various geographical regions.