Spreads of agency mortgage-backed securities (MBS) vary significantly in the cross section and over time, but the sources of this variation are not well understood. We document that, in the cross section, MBS spreads adjusted for the prepayment option show a pronounced smile with respect to the...

This paper reviews the mortgage-backed securities (MBS) market, with a particular emphasis on agency residential MBS in the United States. We discuss the institutional environment, security design, MBS risks and asset pricing, and the economic effects of mortgage securitization. We also assemble...