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。     

主权信用评级的金融市场溢出效应研究——基于欧洲主权债务危机的实证分析

欧洲主权债务危机爆发以来,三大评级机构频繁下调欧元区国家的主权信用评级,这在某种程度上催化了危机的蔓延。危机期间,三大评级机构频繁下调欧元区国家特别是"欧猪五国"的主权信用评级,引起了金融市场的明显波动。本文对2008年10月31日至2012年1月13日期间"欧猪五国"主权信用评级变化的国内、跨国金融市场溢出效应以及不同评级机构主权信用评级信息的金融市场溢出效应分别进行实证研究,得出了一系列结论。     

我国的主权信用评级被低估了吗

本文以1996—2011年间45个国家的宏观经济数据和惠誉的主权信用评级数据,运用一般面板线性回归和有序概率模型研究了我国的主权信用评级是否被低估的问题。结果发现,国际评级机构并没有刻意低估我国的主权信用评级,其对我国主权信用评级的测算方法并不明显有别于其他国家。但是,由于评级体系的倾向性和我国地方政府债务不透明等原因,导致我国的主权信用评级客观上存在被低估的可能。     

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。     

主权债务评级

主权信用评级是信用评级机构进行的对一经济体政府或当局作为债务人履行偿债责任的意愿和能力的评判。在这一评判过程中,评级机构一般对一个经济体经济增长趋势、贸易及国际收支、外汇储备、外债余额及结构、财政收支和相关政策影响等进行考察,最后给出具体评级。一般而言,主权信用评级会包括长期主权信用评级、短期主权信用评级和评级展望三个方面,分别反映不同时间段的偿债能力及中长期信用状况的潜在变化方向。     

中国的主权信用评级是否被低估?北大核心CSSCISSCI

本文以1986至2009年期间120个国家的宏观经济数据和三大评级机构的主权信用评级结果为研究对象;运用面板数据的多元回归模型和有序Probit概率模型研究中国的主权信用评级是否被低估的问题。通过对三大评级机构的定量分析模型进行模拟与验证发现,中国的主权信用评级在20世纪90年代和2001年至2002年前后的确被低估,但2003年以后,随着穆迪、标准普尔等评级机构相继调高我国的主权信用等级,目前我国的模拟评级与实际评级已经基本持平。     

中国的主权信用评级是否被低估?

本文以1986至2009年期间120个国家的宏观经济数据和三大评级机构的主权信用评级结果为研究对象;运用面板数据的多元回归模型和有序Probit概率模型研究中国的主权信用评级是否被低估的问题。通过对三大评级机构的定量分析模型进行模拟与验证发现,中国的主权信用评级在20世纪90年代和2001年至2002年前后的确被低估,但2003年以后,随着穆迪、标准普尔等评级机构相继调高我国的主权信用等级,目前我国的模拟评级与实际评级已经基本持平。     

主权信用评级调整的经济影响北大核心CSSCISSCI

通过总结主权信用评级调整经济影响的相关研究以及国际三大评级机构的评级实践,本文勾勒出主权信用评级调整的主要冲击路径和原理。对于近期我国主权评级被穆迪下调事件,本文认为此次下调在现阶段对中国的影响有限,其最主要的影响在于增加国内企业海外融资成本,未来需重点防范评级机构在短期内集中下调评级所产生的叠加效应。     

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.     

主权评级下调对中亚地区股票市场的冲击——基于哈萨克斯坦的实证

作为衡量主权国家信用风险的主权信用评级,为市场参与者提供了被评级国家正面或者负面的一个信号。通过了解主权信用评级调整情况,股票市场参与者能够知悉被评级国家的经济在未来的发展状况,进行风险预判调整投资行为。中亚地区的金融市场开放时间相对较晚,2006年阿拉木图区域金融中心的建立,标志着哈萨克斯坦股票市场正式融入国际资本市场,同时意味着影响市场变动的因素增多。本文基于哈萨克斯坦2006年到2012年的数据,研究中亚地区股票市场面对主权信用评级调整发生的变化,观察股票市场在主权评级调整时的变化情况,分析探讨可能的原因。文章中借助事件研究方法,量化分析主权评级调整在短期内对市场的影响情况。从实证研究结果来看,主权评级的下调,加剧了哈萨克斯坦的股票市场波动程度,增大金融风险。     

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.     

国际信用评级体系改革与中国评级业发展展望

国际金融危机和欧洲主权债务危机的爆发,凸显出现行国际信用评级体系存在的种种弊端。该文指出,现行国际信用评级体系的根本缺陷在于高度垄断,为此应通过加强内部治理和外部监管推动现有评级行业的改革,并推动国际信用评级行业新秩序的建立。中国应从宏观政策层面出台措施,扶持和推动本国自主信用评级体系的做大做强,并参与到国际信用评级体系的重建中。     

The Real Effects of Credit Ratings: The Sovereign Ceiling Channel

We show that sovereign debt impairments can have a significant effect on financial markets and real economies through a credit ratings channel. Specifically, we find that firms reduce their investment and reliance on credit markets due to a rising cost of debt capital following a sovereign rating downgrade. We identify these effects by exploiting exogenous variation in corporate ratings due to rating agencies' sovereign ceiling policies, which require that firms' ratings remain at or below the sovereign rating of their country of domicile.     

Sovereign credit ratings and bank funding cost: Evidence from Africa

This paper aims to examine the relationship between sovereign credit ratings and funding costs of banks and also the relationship between sovereign credit ratings. Using over 300 banks operating in Africa from 2006 to 2012, the study investigates sovereign ratings’ impact on funding cost. The long term domestic sovereign ratings announced by Fitch and Standard & Poor’s during the period under study were used. The panel made use of Generalized Method of Moments estimation strategy for funding cost. The findings of the study indicate that sovereign ratings upgrades have an inverse and statistically significant relationship with funding costs. The findings suggest that sovereign rating upgrades makes it easier for banks to access funds from the capital and global market at a cheaper cost compared to rating downgrades. The study recommends and encourages emerging economies to use the services provided by credit rating agencies since these agencies may help improve accessibility of funds in the international markets by banks. It is recommended that sovereign rating should be considered as a supplement and not a substitute to our own perceived judgement and research.     

The impact of sovereign rating actions on bank ratings in emerging markets

This paper analyses the effects of sovereign rating actions on the credit ratings of banks in emerging markets, using a sample from three global rating agencies across 54 countries for 1999–2009. Despite widespread attention to sovereign ratings and bank ratings, no previous study has investigated the link in this manner. We find that sovereign rating upgrades (downgrades) have strong effects on bank rating upgrades (downgrades). The impact of sovereign watch status on bank rating actions is much weaker and often insignificant. The sensitivity of banks’ ratings to sovereign rating actions is affected by the countries’ economic and financial freedom and by macroeconomic conditions. Ratings of banks with different ownership structures are all influenced strongly by the sovereign rating, with some variation depending on the countries’ characteristics. Emerging market bank ratings are less likely to follow sovereign rating downgrades during the recent financial crisis period.     

Special Issue on Market Development and Investment Strategies in Asia

Sovereign credit rating actions have attracted considerable attention recently. This study employs a rich and unique data set of ratings from six international agencies to investigate the causes of split sovereign ratings in emerging countries. Three reasons are identified in explaining the relatively high frequency of disagreement across agencies on emerging sovereign ratings. First, rating agencies use different economic factors and different weights on those factors. Second, rating agencies disagree to a greater extent about more opaque issuers. Third, for smaller rating agencies, issuers in their "home region" tend to be more favored. The findings should be of interest to a wide range of participants in global credit markets.     

Towards an early warning system for sovereign defaults leveraging on machine learning methodologies

In this study, we address the topic of credit risk stemming from central governments from a technical point of view. First, we explore various econometric and machine learning techniques to build an enhanced sovereign rating system that effectively differentiates the risk of default among countries. Our empirical results indicate that the machine learning method of XGBOOST has a superior out-of-sample and out-of-time predictive performance. Then, we use the models developed to calibrate a sovereign rating system and provide useful insights into the set-up of a parsimonious early warning system. Our results provide a more concise view of the most robust method for classifying countries’ default risk with significant regulatory implications, given that the efficient assessment of sovereign debt is crucial for effective proactive risk measurement.     

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.     

Investors’ heterogeneous beliefs and the impact of sovereign credit ratings in foreign exchange and equity markets

We propose a model in which sovereign credit news from multiple rating agencies interacts with market heterogeneity. The model illustrates that the first messenger discloses new information while additional messengers play an important role of coordinating heterogeneous beliefs. Empirical investigations based on sovereign credit ratings, foreign exchange and equity markets confirm that rating news coordinates investors’ beliefs. Sovereign credit rating news from both types of messenger induces a significant impact on exchange rates and stock indices. Volatility measures increase in response to news from the first messenger while ex-post volatility reduces following news from an additional messenger.