Risk, ambiguity and sovereign rating, International Economics and Economic Policy, 2014 (original) (raw)

Risk, ambiguity, and sovereign rating

International Economics and Economic Policy, 2014

Decisions of investing in sovereign assets involve both risk and ambiguity. Ambiguity arises from unknown elements characterizing the value of a generic sovereign. In presence of ambiguity, ambiguity-averse investors are prone to pay for obtaining summary information such as ratings which reduces ambiguity. Ambiguity-neutral and ambiguity-averse investors, then, make decisions on the basis of different informative sources. By presenting a simple model of sovereign rating under ambiguity, three facts occurring in today's financial markets are explained. Sovereign ratings influence decisions of investment of ambiguity-sensitive individuals. Rating-dependent regulations create distortions in financial markets by institutionalising specific summary signals. Providing ratings may be a profitable activity. Some final suggestions propose future areas of theoretical and empirical research.

What drives differences of opinion in sovereign ratings? The roles of information disclosure and political risk

International Journal of Finance & Economics, 2017

This paper investigates the causes of split sovereign ratings across S&P, Moody's, and Fitch for 64 countries from 1997 to 2011. We identify that split sovereign ratings are not symmetric, with S&P tending to be the most conservative agency. We find that opaque sovereigns are more likely to receive split ratings. Political risk plays a highly significant role in explaining split ratings and dominates economic and financial indicators. Out‐of‐sample model performance is enhanced by capturing political risk. Government information disclosure affects split ratings between Moody's and Fitch in emerging countries. The study implies an incentive for governments to reduce political uncertainty and to enhance transparency.

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

The European Journal of Finance, 2019

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.

On sovereign ratings: observations and implications

, as much of this note draws on that body of work. I would also like to thank John Chambers (S&P) and Mauro Leos (Moody's) and my IDB colleagues Ed Bartholemew, Eduardo Borensztein and my ex colleague Ugo Panizza for useful discussions on ratings, as well as the participants in the Sovereign Risk Seminar, held at the BIS January 8/9 2013 and particularly Bob McCauley at the BIS for his helpful and constructive suggestions. Remaining mistakes however are my own. All the opinions expressed are solely my own and do not necessarily reflect those of the Inter-American Development Bank, those of its Board of Directors, or those of the countries they represent.

Ambiguity in asset markets: theory and experiment

Review of Financial …, 2010

This paper studies the impact of ambiguity and ambiguity aversion on equilibrium asset prices and portfolio holdings in competitive financial markets. It argues that attitudes toward ambiguity are heterogeneous across the population, just as attitudes toward risk are heterogeneous across the population, but that heterogeneity of attitudes toward ambiguity has different implications than heterogeneity of attitudes toward risk. In particular, when some state probabilities are not known, agents who are sufficiently ambiguity averse find open sets of prices for which they refuse to hold an ambiguous portfolio. This suggests a different cross-section of portfolio choices, a wider range of state price/probability ratios and different rankings of state price/probability ratios than would be predicted if state probabilities were known. Experiments confirm all of these suggestions. Our findings contradict the claim that investors who have cognitive biases do not affect prices because they are infra-marginal: ambiguity averse investors have an indirect effect on prices because they change the per-capita amount of risk that is to be shared among the marginal investors. Our experimental data also suggest a positive correlation between risk aversion and ambiguity aversion that might explain the "value effect" in historical data.

Ambiguity and asset prices: an experimental perspective

2006

Most of the economics and finance literature assumes that individual agents obey the Savage axioms; that is, they maximize expected utility according to subjective priors. However, Knight, Ellsberg and others argue that individual agents distinguish between risk (known probabilities) and uncertainty, or ambiguity (unknown probabilities), and that individual agents may display aversion to ambiguity, just as they display aversion to risk. This paper studies the impact of ambiguity aversion on equilibrium asset prices and portfolio holdings in competitive financial markets. It argues that attitude toward ambiguity is heterogeneous in the population, just as attitude toward risk is heterogeneous in the population, but that heterogeneity in attitude toward ambiguity has different implications than heterogeneity in attitude toward risk: agents who are sufficiently ambiguity averse find open sets of prices for which they refuse to hold an ambiguous portfolio. This leads to a wider range of state price densities and to potential reversals of ranking of state price densities. Experiments confirm the theoretical predictions.

A Ratings Based Approach to Measuring Sovereign Risk

Social Science Research Network, 2007

We propose a new approach to measuring sovereign default risk. We use sovereign credit ratings and historical default rates provided by credit rating agencies to construct a measure of ratings implied expected loss. We compare our measure of expected loss from sovereign defaults with stand-alone credit ratings and also examine its relationship with credit default swap spreads. We show that our measure is more informative for measuring sovereign risk. We reexamine the fundamental determinants of sovereign risk and find further evidence to support the debt intolerance and original sin explanations for country risk. This study contributes an improved understanding of the value of sovereign credit rating teams in assessing the long-term country risks accompanying emerging market investments.

Sovereign credit ratings

Current Issues in Economics and Finance, 1995

Sovereign ratings are gaining importance as more governments with greater default risk borrow in international bond markets. But while the ratings have proved useful to governments seeking market access, the difficulty of assessing sovereign risk has led to agency disagreements and public controversy over specific rating assignments. Recognizing this difficulty, the financial markets have shown some skepticism toward sovereign ratings when pricing issues.

Sovereign risk assessment and agency credit ratings

European Financial Management, 1996

Sovereign ratings are gaining importance as more governments with greater default risk borrow in international bond markets. Howevel; while the ratings have proved useful to governments seeking market access, the difficulty of assessing sovereign risk has led to agency disagreements and public controversy over specific rating assignments. Recognising this difficul& the financial markets have shown some scepticism toward sovereign ratings when pricing issues.