精选优质文档-倾情为你奉上英文原文(原文也可以直接将PDF版打印)ASSESSING CREDIT OR DETERMINING QUANTITY?THE EVOLVING ROLE OF RATING AGENCIESLynnette D. Purda*This version: April 21, 2011AbstractOver the past ten years, credit rating agencies have come under intense criticism from both practitioners and academics, first for their failure to identify problems resulting in bankruptcies at Enron and Worldcom and second for providing overly optimistic ratings for structured finance products. While many investors