We study credit ratings on subprime and Alt-A mortgage-backed-securities (MBS) deals issued between 2001 and 2007, the period leading up to the subprime crisis. The fraction of highly rated securities in each deal is decreasing in mortgage credit risk (measured either ex ante or ex post),...

This article is divided into four sections. In the first one, we describe the origin and history of investment banking, with particular focus on the economic conditions that led to its birth in the United States. The second part considers those products offered by investments banks which are...