【内容摘要】The corporate bond market in the United States had long been plagued by information opacity due to lack of price and other trading information. The Trade Reporting and Compliance Engine (TRACE), introduced in 2002 to address this problem, provides a natural experiment for examining the economic consequences of disclosure of trading information. While it may not be surprising that bond prices contain incremental information about firms’default risk beyond stock prices and accounting numbers, importantly we show that bond rating agencies are more responsive to changes in bond prices when transaction information is disseminated on TRACE; bond ratings become timelier and more accurate in warning of default after the introduction of TRACE.