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Zorn, and seminar participants at MIT and West Virginia University for helpful comments. We also thank Glenn Canner for assistance in obtaining some of the data, and Shawn Rohlin and Michael Eriksen for excellent research assistance. Any errors are our own. Secondary markets for credit are widely believed to improve efficiency and increase access to credit. In part, this is because of their greater ability to manage risk. Nevertheless, the degree to which secondary markets expand access to credit is virtually unknown. Using the mortgage market as an example, we begin to fill that gap. Our conceptual model suggests that secondary credit markets have potentially ambiguous effects on interest rates, but unambiguous positive effects on the number of loans issued. We focus our empirical analysis on the latter using 1992-2004 HMDA files for conventional, conforming, home purchase loans in conjunction with Census tract data. Findings confirm that an active secondary market increases mortgage origination rates. Between 2000 and 2004, for example, conventional loan purchases increased the share of applications originated by 15.6 percent, on average, roughly halving the denial rate. Further, in the high ris