Presentation on theme: "Eduardo Cavallo, IADB Andrew Powell, IADB Roberto Rigobon, MIT."— Presentation transcript:
Eduardo Cavallo, IADB Andrew Powell, IADB Roberto Rigobon, MIT
Motivation Do credit agencies add informational value to an already well functioning financial market? Rating changes are usually anticipated. Hence, they should have been incorporated in interest rates and other financial variables. In sovereign debt, does the rating adds information beyond the information already in the interest rate? Very difficult to disentangle informational content of credit ratings
What do we do? Evaluate informational content using methodology robust to several misspecification errors Evaluate impact of rating changes on stock markets, future spreads, and exchange rates – after controlling for current interest rates and VIX
What we find? Ratings provide information in additional to interest rates Rating upgrades Reduce future interest rate spreads Increase stock markets Appreciate exchange rates Results are quite robustness
Methodology Technically we are asking if the interest rate is a sufficient statistic for the credit rating. We have to allow for misspecification. To test this hypothesis we assume that there is an underlying fundamental for the economy, and interest rates and credit ratings are imperfect measures of it. We evaluate the “sufficient statistic” property of the interest rate trying to explain other financial variables Future spread Stock market Exchange rate
Methodology Idea If the true model is then we can estimate by OLS or using ratings as IV. Test Under the null hypothesis the OLS estimate and the IV estimate are identical. Under the alternative hypothesis, the OLS and IV are different. The OLS is biased because of EIV, but IV is consistent.
Methodology After we have found that the rating has informational content, we run a horse race between interest rates and ratings. We estimate in a window surrounding credit rating changes. (+/- 10 days) Fixed effect per event Cumulative returns – to deal with endogeneity and anticipation.
Data Source: Bloomberg Daily information 32 emerging market economies January 1 st 1998 and April 25 th 2007 Macro variables: stock market, interest rate spread, dollar exchange rate, VIX Ratings: Moody, S&P, Fitch – transformed to a numerical scale. Unbalanced panel with ~80k observations
Results Pooled all credit rating events. Fixed effects for each event. Analyze window of 21 days surrounding credit rating change. Use cumulative returns. We are not concerned with interpretation of coefficient. No attempt to disentangle channel of propagation.
Results Table 5: summary Spreadt+1Stock MarketExchange Rate Standard & Poor's (downgrades + upgrades) 0.0010.0180.848 Standard & Poor's (downgrades) 0.0100.8000.436 Standard & Poor's (upgrades) 0.0010.1400.001 Fitch (downgrades + upgrades) 0.4300.6000.001 Fitch (downgrades) 0.9600.001 Fitch (upgrades) 0.1900.0010.031 Moodys (downgrades + upgrades) 0.0660.0610.082 Moodys (downgrades) 0.3550.0530.001 Moodys (upgrades) 0.0780.0090.001 Standard & Poor's - 5 day window (all) 0.0010.0780.771 Standard & Poor's - 5 day window (downgrades) 0.0010.7700.018 Standard & Poor's - 5 day window (upgrades) 0.1000.0170.001 Standard & Poor's - 20 day window (all) 0.0010.6600.850 Standard & Poor's - 20 day window (downgrades) 0.001 0.670 Standard & Poor's - 20 day window (upgrades) 0.0010.0680.001 Standard & Poor's - Without contemporanous change in rating 0.0010.1000.250 Rejection rate 2 75%63%
Lessons Informational content Around credit rating changes, ratings provide information beyond interest rates EIV interpretation allows for a robust methodology Robust to specification changes Even though they are anticipated
Lessons Informational content Around credit rating changes, ratings provide information beyond interest rates EIV interpretation allows for a robust methodology Robust to specification changes Even though they are anticipated Rating changes Upgrades Decrease future spreads (0.7% per notch) Increase stock market (0.2% per notch) Appreciate real exchange rate (0.2% per notch) Downgrades Decrease future spreads (0.6% per notch) No impact on stock markets No impact on exchange rates
Results Does changes in asset class have larger impact? We find that changing the asset class has no additional effect for the rating variable. What about outlook changes? Replicate the results for outlook. Estimate degree of anticipation using the outlook change prior to the rating change.
Conclusions Ratings provide information in additional to interest rates Different agencies provide different information Rating upgrades Reduce future interest rate spreads Increase stock markets Appreciate exchange rates All even after controlling for, fixed effects, interest rate and VIX. Robustness Anticipation affects the quantitative results but not the qualitative message Outlooks provide same conclusions