Most mortgages in the U.S. are securitized in agency mortgage-backed securities (MBS). Yield spreads on these securities are thus a key determinant of homeowners' funding costs. We study variation in MBS spreads over time and across securities, and document a cross-sectional smile pattern in MBS...

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...