Rating Inflation versus Deflation:On the Pro-cyclical Credit Ratings
解释了为何国际三大评级机构同时被指责评级过松（膨胀）和过严（紧缩），并证明信用评级具有顺周期性：繁荣期易膨胀，衰退期易紧缩。
The big three international credit rating agencies,Moody's,Standard and Poor's,and Pitch,have played a critical role in the financial markets.However,since the recent global financial crises,the big three have been widely criticized.Some accuse them of too lax in rating structured finance products,thus bearing a responsibility in the subprime crisis.Others blame them too restrictive,downgrading many companies and countries' ratings without listening to their explanations.This article offers a rationale to reconcile the above two seemingly inconsistent accusations.We show that both rating inflation and rating deflation can happen in the equilibrium path.Furthermore,we show that credit rating is pro - cyclical:rating inflation is more likely to happen in a boom,while rating deflation is more likely in a recession.