债券评级机构变更——基于评级选购与评级迎合视角

本文以2008年至2017年的公司债券为样本,研究了发行人变更评级机构的影响,以此来解释评级市场上发行人频繁变更评级机构的现象。本文发现发行人变更评级机构后,其信用等级得到显著提升。发行人变更评级机构的行为对信用等级的影响在以下两种情形中更显著:一是当发行人所处行业或评级机构所在的评级市场竞争激烈时;二是当发行人主体评级位于AA信用等级的临界点时。进一步研究发现,考虑到评级机构变更与信用等级之间的交互影响,变更评级机构的发行人整体上可实现发债成本的降低。但该类发行人未来的违约风险增加、经营业绩下降。最后,本文发现债券发行规模较大以及非国有发行人更倾向于变更评级机构来提高信用等级。本文通过分析发行人更换信用评级机构的动机和后果,为监管部门构建以评级质量为导向的良性竞争环境提供借鉴参考。     

信用评级变动能反映企业真实财务信息吗?——基于财务重述的视角

本文以2007-2018年拥有主体信用评级的A股上市公司为研究对象,利用企业财务错报在未来被重述这一场景,检验主体信用评级变动能否反映企业真实财务信息。研究发现,评级机构在发债企业财务错报年显著下调了主体信用评级,而在重述公告发布年没有上述现象,这表明主体信用评级下调反映了企业的真实财务信息。在控制内生性影响后,结论仍然成立。进一步研究发现,发债企业当期财务错报涉及盈余时,主体信用评级被下调的幅度更大,说明评级机构更加关注与盈余相关的财务信息。机制分析表明,评级机构维护自身声誉是主体信用评级变动能够反映企业真实财务信息的主要机制。此外,主体信用评级被下调还导致了资本市场投资者的负面反应。本文的研究结果为主体信用评级变动反映企业真实财务信息提供了直接的证据支持,揭示了主体信用评级的信息含量,也对理解中国情境下评级机构调整主体信用评级的行为动机提供参考。     

多重信用评级与债券融资成本——来自中国债券市场的经验证据

本文揭示了多重信用评级的信息生产机制和信用认证机制,排除了“信用评级购买”假说对于多重评级动机的解释,研究发现:多重信用评级有利于降低债券融资成本;相对于不一致的多重信用评级,一致的多重信用评级更有利于降低债券融资成本。在多重信用评级中,相对于评级机构均为“发行人付费”模式,兼有“投资者付费”模式的信用评级更有利于降低债券融资成本。此外,当多重信用评级的评级意见不一致时,平均评级的信息含量最高,即综合不同信用评级所包含的多种信息比任何单一信用评级更加具有信息含量。本研究为我国债券市场双评级制度提供了理论和经验证据的支持,有助于完善多元化信用评级制度和债券市场监管制度,并提示发债企业可以通过多重信用评级向市场传递更多和更具效度的评级信息,以弥补单一信用评级的信息不足和评级结果失准,减少投资者决策的不确定性,从而降低债券融资成本。     

Understanding credit ratings quality: Evidence from UK debt market participants

This study seeks to identify: (i) the demand for corporate bond ratings provided by credit ratings agencies (CRAs); (ii) how issuers select CRAs; and (iii) to better understand ratings quality, a term widely used by commentators, politicians and regulators, but under-explored in the academic literature. Interviews identify the principal source of demand for rating information is to reduce agency conflicts between issuers and investors. Issuers typically engage between one and three credit ratings agencies to rate their debt, implying a heterogeneous demand for ratings services, and different levels of ratings quality. However, ratings quality extends beyond competence and independence to include factors relating to professional judgment, communication, transparency, and the quality and continuity of analytic staff. Findings were discussed in the light of the ongoing international policy debate concerning CRAs.     

Relative default rates on corporate loans and bonds

We use two alternative matched-set methodologies to examine for differences in loan and bond default rates among US non-financial corporate issuers. Under both methodologies, the data indicate that loan default rates are roughly 20% lower than the bond default rates due to issuers that default on their bonds but avoid bankruptcy and avoid defaulting on their loans. For a small number of European issuers, the data suggest a similar reduction in loan default rates relative to bond default rates. However, the European results differ qualitatively from the US results, due likely to differences in US and European bankruptcy regimes, as well as the larger role of bank debt on most European issuers’ balance sheets. These results have important implications for investors, bank supervisors, and rating agencies that assess the relative expected credit losses on loans versus bonds.     

Rating agencies in the face of regulation

This paper develops a theoretical framework to shed light on variation in credit rating standards over time and across asset classes. Ratings issued by credit rating agencies serve a dual role: they provide information to investors and are used to regulate institutional investors. We show that introducing rating-contingent regulation that favors highly rated securities may increase or decrease rating informativeness, but unambiguously increases the volume of highly rated securities. If the regulatory advantage of highly rated securities is sufficiently large, delegated information acquisition is unsustainable, since the rating agency prefers to facilitate regulatory arbitrage by inflating ratings. Our model relates rating informativeness to the quality distribution of issuers, the complexity of assets, and issuers' outside options. We reconcile our results with the existing empirical literature and highlight new, testable implications, such as repercussions of the Dodd-Frank Act.     

“投资人付费”vs.“发行人付费”:谁的信用评级质量更高？

本文选择2011-2015年被中债资信覆盖的发债A股上市公司作为主要研究对象,比较了“投资人付费”与“发行人付费”模式下的评级质量高低。研究发现:(1)与“发行人付费”评级相比,采用“投资人付费”模式的中债资信所作评级显著更低。(2)与“发行人付费”评级相比,当采用“投资人付费”模式的中债资信所作评级越低时,发行人未来盈利能力越差、预期违约风险越高,投资者要求的风险补偿也越高,这表明“投资人付费”模式下的信用评级质量更高。(3)“发行人付费”模式的评级结果可以在一定程度上反映公司的内部私有信息,但由于同时存在独立性缺失问题,“发行人付费”模式的信用评级质量仍然不如“投资人付费”模式的信用评级质量,这说明独立性对于评级机构尤其重要。     

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.     

Non-rating revenue and conflicts of interest

Rating agencies produce ratings used by investors, but obtain most of their revenue from issuers, leading to a conflict of interest. We employ a unique data set on the use of non-rating services, and the associated payments, in India, to test if this conflict affects ratings quality. Agencies rate issuers that pay them for non-rating services higher (than agencies not hired for such services). Such issuers also have higher default rates. Both effects are increasing in the amount paid. These results suggest that issuers which hire agencies for non-rating services receive higher ratings despite having higher default risk.     

Rating shopping and rating inflation in Israel

Firms may exploit the option of choosing among different rating agencies in order to pick the highest rating offered. This possibility, known as rating shopping, is relatively limited on the US corporate bond market because the two main rating agencies (S&P and Moody's) rate virtually all large bond issuers. In this study, we use the data on corporate bond ratings assigned by two Israeli rating agencies affiliated with S&P and Moody's during the period 2004–2012. We show that while one agency (Midroog) systematically assigned higher ratings, the ratings of the other agency (S&P-Maalot) were inflated due to rating shopping. However, despite the many features that encourage rating inflation, the resulting distortion was relatively small (one notch). This may be a fair price for maintaining a competitive rating industry.     

Market structure and rating strategies in credit rating markets – A dynamic model with matching of heterogeneous bond issuers and rating agencies

This paper investigates the impact of rating agencies in a market with asymmetric information. In particular, the role of credit rating agencies as an intermediary between investors and bond issuers is discussed. We model this setting in a dynamic framework in which both rating agencies and bond issuers are of heterogeneous quality. Rating agencies can apply costly research technology to reveal the fundamental nature of bond issuers and engage in rating smoothing. We show that rating smoothing can compensate for low research quality, even though it is accompanied by a quality deterioration in the rating market and market clustering. Moreover, low-quality bond issuers have a general tendency to match with low-quality rating agencies. If investors place a strong emphasis on the reputation of rating agencies, rating markets also tend to be strongly clustered.     

The impact of sovereign credit ratings on Eurobond yields: Evidence from Africa

The importance of sovereign credit ratings and Eurobonds issued by governments have come to the fore in Africa in the last decade. We examine whether changes in sovereign credit ratings impact Eurobond yields in 8 countries over the period of 2014–2019. Our approach reviews rating changes impact on Eurobond yields utilising the event study methodology. Our findings reflect that, on average, close to a third of rating actions directly impact bond yields in African countries. The statistically significant events include the downgrades of South Africa and Namibia to non-investment grade in 2017 reflecting critical transitions and bond investors’ reactions. Overall, the low percentage of a third, relative to previous international studies, suggests that largely rating changes are anticipated, do not have much new information and perhaps the perceived power of credit rating agencies may be overstated. In our view, the results reflect that pre-announcements of rating review dates since 2014 makes rating actions predictable and less impactful to bond yields. In addition, they reflect that bond investors adjust in real time as new information come in, resulting in less reliance on the opinions of CRAs and using their own assessments.     

信用评级收费模式:机制与选择

本文对资信评级机构的收费模式进行了经济学分析,认为由于声誉机制的作用和信息交易中搭便车因素的影响,中小型评级机构只能够对投资者收费,大型评级机构才可能采取向证券发行人收费的模式。中国的资信评级机构从历史信誉和公司规模都是中小型机构,采取对证券发行人免费评级、向投资者收费的模式是当前我国评级机构的必然选择。     

Can rating agencies look through the cycle?

Rating agencies claim to look through the cycle when assigning corporate credit ratings, which entails that they are able to separate trend components of default risk from transitory ones. To test whether agencies possess this competence, I take market-based estimates of 1-year default probabilities of corporate bond issuers and estimate their long-run trend using the Hodrick-Prescott filter, local regression, or centered moving averages. I find that ratings help identify the current split into trend and cycle. In addition, rating stability is similar to the one of hypothetical ratings based on long-term trends. The results are robust to the use of different filter techniques. They are confirmed by a model-free analysis, which shows that ratings predict future changes in market-based default probability estimates. Since the examined trends are forward-looking in the sense that the trend filtering algorithms use future data, agency ratings exhibit important characteristics one would expect from ratings that see through the cycle.     

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。     

金融中介机构竞争的市场反应--来自信用评级机构的证据北大核心

目前已有研究认为金融中介机构竞争会带来市场效率的提高,本文利用2012-2017年债券市场的微观数据研究“发行人付费”模式评级机构之间的竞争对评级结果的影响。研究发现,评级机构竞争会导致评级结果膨胀与评级质量下降。进一步研究发现,当评级竞争加剧时,“发行人付费”模式的评级机构会对有较多业务联系的企业放松评级标准,给予更高信用评级。我们的研究也发现评级机构的外资背景、承销商的良好声誉和媒体关注均有助于减小“发行人付费”模式下评级机构竞争的负面影响。同时,债券市场评级竞争还存在对股票市场的溢出效应,评级竞争导致的评级质量下降也降低了股票市场的信息效率。这说明,“发行人付费”模式下的评级机构竞争会降低资本市场的信息效率,“投资者付费”模式的推广和评级行业的对外开放有助于改善国内评级行业的评级质量。本文的研究也为国内债券市场进一步发挥双评级、多评级以及不同模式评级的交叉验证作用提供了一定证据支持。     

Differences of opinion and selection bias in the credit rating industry

Many regulations use private sector credit ratings to determine investment prohibitions and capital requirements for institutional portfolio investments. These regulations implicitly assume that different agencies have equivalent rating scales, despite the fact that some agencies assign systematically higher ratings than others. We assess the appropriateness of these regulatory practices by testing whether observed rating differences reflect different rating scales or simply result from sample selection bias. Our analysis reveals only limited evidence of selection bias. We also ask what types of firms of firms are most likely to seek ratings from the agencies with higher rating scales. Our analysis uncovers no evidence that firms seek ratings from these agencies to clear specific regulatory hurdles or to reduce ex ante uncertainty about default risk.     

The role of ESG scoring and greenwashing risk in explaining the yields of green bonds: A conceptual framework and an econometric analysis

This article aims to investigate the factors that most influence the yields of public sector and corporate green bonds besides those conveyed by the conventional finance theory (e.g., rating, volatility, maturity). To accomplish that, we first develop a theoretical framework that postulates the negative relationship between the size of the underlying project financed by a green bond issuance, the use of the ESG metrics to quantify such impact, as well as the positive relationship between the risk of greenwashing practices by the issuer, and the yield to maturity of the green bond. We then provide an empirical validation of our conceptual framework by estimating multiple regression models applied to two distinct samples of public and corporate green bonds issued globally in the 2012–2020 period. The reliability of our results is confirmed by further exploring the effects of some key determinants on the yield spread of green versus comparable ordinary bonds of corporate issuers. Our findings corroborate our theoretical predictions showing that investors are inclined to accept lower returns in exchange for contributing to the funding of infrastructure projects with greater impact on the sustainability of target communities or territories and require higher premia as a form of compensation when being exposed to higher risk of greenwashing by issuers. At corporate level, greenwashing risk is higher among manufacturing (rather than services) firms but more pronounced in the financial sector. At public level, greenwashing strategies may be more easily pursued by multinational or sovereign issuers rather than local governments as the former's greater distance from communities enables them to elude investors' controls. Important recommendations are drawn for investors, rating agencies, and policymakers.     

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.