主权评级对市场影响的实证分析

主权评级作为市场信息传递中介备受质疑。本文考察了目前欧洲债务危机中的主权评级,采用固定效应模型分别研究三大评级机构主权评级观察及评级降级对欧元区国家融资成本的市场影响。结果表明,主权评级对于市场长期影响不是很大,其中独立的降级影响不显著;评级负面观察的市场影响较评级降级的独立影响显著;评级观察及降级变化尽管对高级别国家的影响有限,但对A级以下的国家有明显的冲击影响。评级结果可能加剧了欧洲债务危机的解决难度。     

Market-implied ratings and their divergence from credit ratings

In this article, we investigate the divergence between credit ratings (CRs) and Moody's market-implied ratings (MIRs). Our evidence shows that rating gaps provide incremental information to the market regarding issuers' default risk over CRs alone in the short horizon and outperform CRs over extended horizons. The predictive ability of rating gaps is greater for more opaque and volatile issuers. Such predictability was more pronounced during the 2008 financial crisis but weakened in the post–Dodd–Frank Act period. This finding is consistent with credit rating agencies’ efforts to improve their performance when facing regulatory pressure. Moreover, our analysis identifies rating-gap signals that do (do not) lead to subsequent Moody's actions to place issuers on negative outlook and watchlists. We find that negative signals from MIR gaps have a real economic impact on issuers’ fundamentals such as profitability, leverage, investment, and default risk, thus supporting the recovery-efforts hypothesis.     

The Information Content of Ratings: An Analysis of Australian Credit Default Swap Spreads

We examine the information content of Australian credit rating announcements by measuring the abnormal changes in credit default swap (CDS) spreads. CDS spreads provide a direct view of credit quality and thus should impound information quickly when investors receive new credit risk related information via a rating event. Using an event study methodology, we show that watch downs and rating upgrades contain valuable information even after controlling for sources of contamination. We find that watch downs elicit statistically significant market reactions, while subsequent downgrades are anticipated. Upgrades are associated with a significant but small abnormal reduction in CDS spreads, whereas watch ups appear to contain no new information.     

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。     

Characteristics and Information Value of Credit Watches

We analyze credit watch and rating actions to better understand the role of credit watches in the credit rating process. We find that watch actions are more frequently prompted by specific, publicly known events than are rating actions. The likelihood that a watch action precedes a rating action varies systematically with proxies for investor demand for credit quality information and the adverse consequences of issuing a rating change prematurely. Credit watches occur more often in response to deterioration in credit quality, and issuers make concerted efforts to address the concerns that prompted down watches. Down watches are less likely than up watches to indicate the direction of the subsequent rating change. Watch announcements are associated with abnormal stock returns, indicating that credit watch actions are significant information events. Our results suggest that credit watches are informative and facilitate the stability of ratings by allowing firms to correct deficiencies and prevent downgrades.     

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.     

Do managers withhold bad news from credit rating agencies?

Research documents that managers, on average, withhold bad news and emphasize good news in their public disclosures. We ask whether the same is true in their private communications with credit rating agencies. We study how rating agencies anticipate and react to public information events as a function of their access to rated firms’ private information. We show that, in terms of ratings downgrades, rating agencies exhibit relatively more anticipation and less reaction to negative (compared to positive) public information events when they have more access to private information. Our results are strongest when firms are most optimistic in their public disclosures and are not due to rating agencies focusing their efforts on downside risk. Overall, we find consistent evidence that rated firms provide less optimistic information to rating agencies in their private communications and that this information is reflected in credit ratings.

     

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.     

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.     

Are international accounting standards more credit relevant than domestic standards?

We examine whether the credit relevance of financial statements, defined as the ability of accounting numbers to explain credit ratings, is higher after firms are required to report under International Financial Reporting Standards (IFRS). We find an improvement in credit relevance for firms in 17 countries after mandatory IFRS reporting is introduced in 2005; this increase is higher than that reported for a matched sample of US firms. The increase in credit relevance is particularly pronounced for higher risk speculative-grade issuers, where accounting information is predicted to be more important; and for IFRS adopters with large first-time reconciliations, where the impact of IFRS is expected to be greater. These tests provide reassurance that the overall enhancement in estimated credit relevance is driven by accounting changes related to IFRS adoption. Our results suggest that credit rating analysts’ views of economic fundamentals are more closely aligned with IFRS numbers, and that analysts anticipate at least some of the effects of the IFRS transition.     

“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。     

Does sovereign debt ratings news spill over to international stock markets?

The evidence here indicates that sovereign debt rating and credit outlook changes of one country have an asymmetric and economically significant effect on the stock market returns of other countries over 1989–2003. There is a negative reaction of 51 basis points (two-day return spread vis-á-vis the US) to a credit ratings downgrade of one notch in a common information spillover around the world. Upgrades, however, have no significant impact on return spreads of countries abroad. Closeness (e.g., geographic proximity) and emerging market status amplify the effect of a spillover. Downgrade spillover effects at the industry level are more pronounced in traded goods and small industries.     

Credit ratings and excess value of diversification

We investigate the impact of credit ratings on the valuation of diversification. Our empirical results indicate that the existence and level of credit ratings are associated with a lower negative effect of diversification. Further analysis reveals that the mitigating effect of credit ratings on the diversification discount is more pronounced for firms with more severe information asymmetry. In addition, both a change in firm status from no rating to being rated and a change in rating level from low to high lead to a significant reduction in the diversification discount. An event study on diversification buttresses the findings by showing that the market has a less negative reaction to rated and higher-rated firms around the announcement of diversifying mergers. Our results are robust to alternative techniques used to control for potential endogeneity bias, to controlling for corporate governance, and to different sample periods. Overall, the evidence suggests that credit ratings reduce information asymmetry problems and thus mitigate the diversification discount.     

Market Implied Ratings and Financing Constraints: Evidence from US Firms

Financing constraints have been found to play an important role in several aspects of firm behavior, but no attention has been given to their effects on credit ratings. In this paper we analyze a unique and comprehensive data set for US firms rated by Fitch over the period 2001–07. We employ Fitch's market implied ratings derived from bond and equity prices. The analysis finds evidence that financial variables are more important in predicting credit ratings for firms likely to face financing constraints. We conclude that the financing constraint is an important dimension in the market implied ratings process. Our findings are of relevance to managers, investors and rating agencies seeking to understand the mechanism through which financing constraints affect credit ratings.     

News spillovers in the sovereign debt market

We study the effect of a sovereign credit rating change of one country on the sovereign credit spreads of other countries from 1991 to 2000. We find evidence of spillover effects; that is, a ratings change in one country has a significant effect on sovereign credit spreads of other countries. This effect is asymmetric: positive ratings events abroad have no discernable impact on sovereign spreads, whereas negative ratings events are associated with an increase in spreads. On average, a one-notch downgrade of a sovereign bond is associated with a 12 basis point increase in spreads of sovereign bonds of other countries. The magnitude of the spillover effect following a negative ratings change is amplified by recent ratings changes in other countries. We distinguish between common information and differential components of spillovers. While common information spillovers imply that sovereign spreads move in tandem, differential spillovers are expected to result in opposite effects of ratings events across countries. Despite the predominance of common information spillovers, we also find evidence of differential spillovers among countries with highly negatively correlated capital flows or trade flows vis-á-vis the United States. That is, spreads in these countries generally fall in response to a downgrade of a country with highly negatively correlated capital or trade flows. Variables proxying for cultural or institutional linkages (e.g., common language, formal trade blocs, common law legal systems), physical proximity, and rule of law traditions across countries do not seem to affect estimated spillover effects.     

债券市场的评级信息能改善股票市场信息环境吗?——来自分析师预测的证据

本文研究发现,信用评级增加了分析师预测的公共信息,同时没有减少分析师预测的私有信息,即信用评级信息能够改善股票市场信息环境。具体地,本文利用2006-2016年上市公司数据实证发现,信用评级能显著提高分析师预测精度、降低分析师预测分歧度与乐观偏差,且这种效应在信息不对称程度高、低能力分析师跟踪的企业以及外资参股的评级机构中更加显著,这说明信用评级向分析师提供了新的信息。进一步地,信用评级只增加了分析师预测的公共信息,对私有信息没有显著影响,同时也不影响分析师的调研行为,上述结论表明信用评级信息披露并不影响分析师拥有私有信息的优势,且信用评级机构与分析师之间存在互补而非替代关系。因此,金融监管应该加强对评级机构尽职调研的要求,充分发挥信用评级机构的信息中介功能。     

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。     

Fiscal Transparency,Fiscal Performance and Credit Ratings

Fiscal transparency can provide policymakers with incentives to adopt better policies by enhancing the public debate on the design and sustainability of fiscal policy and establishing accountability for their implementation. Fiscal transparency can also reduce uncertainty about fiscal policy and fiscal outturns by providing more information on the underlying fiscal position and fiscal risks. Both effects suggest that countries should benefit from adopting transparency enhancing policies through better market assessments of their sovereign risk. In this paper, we investigate whether fiscal transparency has an effect on market perceptions of sovereign risk, as measured by sovereign credit ratings, and if so, through which channels. We find that fiscal transparency has a positive and significant effect on ratings – one standard deviation increase in fiscal transparency increases credit ratings by 0.7 and 1 notches (or steps in the credit rating scale) in advanced and developing economies, respectively – but its effect works through different channels in advanced and developing economies. In advanced economies, fiscal transparency is associated with better fiscal outcomes, leading indirectly to higher credit ratings. In developing economies, the direct uncertainty‐reducing effect of fiscal transparency seems to be more important. Indeed, the effect of fiscal transparency on fiscal performance is found to increase with the level of institutional development.     

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。     

Sovereign rating actions and the implied volatility of stock index options

This paper examines the interaction between the equity index option market and sovereign credit ratings. S&P and Moody's signals exhibit strong impact on option-implied volatility while Fitch's influence is less significant. Moody's downgrades reduce the market uncertainty over the rated countries' equity markets. Strong causal relationships are found between movements in the option-implied volatility and all credit signals released by S&P and Fitch, but only actual rating changes by Moody's, implying differences in rating agencies' policies. The presence of additional ratings tends to reduce market uncertainty. The findings highlight the importance of rating information in the price discovery process and offer policy implications.