Abstract This article explores the causes and consequences of cross-country variation in mortgage market structure. It draws on insights from several fields: urban economics, asset pricing, behavioral finance, financial intermediation, and macroeconomics. It discusses lessons from the credit boom, the challenges of mortgage modification in the aftermath of the boom, consumer financial protection, and alternative mortgage forms and funding models. The article argues that the USA has much to learn from mortgage finance in other countries, and specifically from the Danish implementation of the European covered bonds system.