On October 7, the GAO published a report to help policymakers assess proposals for changing the single-family housing finance system and consider ways to make it more effective and efficient. To this end, the report first describes the market developments since 2000 that have led to changes in the federal government’s role in single-family housing finance. Most notably, the GAO found that as the market share of nonprime mortgages grew before the 2007-2009 financial crisis, the share of new mortgage originations insured by federal entities (including Fannie Mae and Freddie Mac) fell dramatically before rising sharply again during and after the crisis. Second, the report analyzed whether and how these market developments created challenges for the housing finance system. The GAO concluded that mortgage markets since 2000 have challenged the housing finance system, revealing the following weaknesses: (i) misaligned incentives between originators and securitizers on the one hand, and borrowers and investors on the other, as the former did not share the risks of the latter; (ii) a lack of reliable information and transparency for borrowers because originators were not required to share certain information; (iii) excessive risk taking due to a loosening of underwriting standards prior to the financial crisis; and (iv) a lack of federal oversight (since addressed by Congress through the FHFA and CFPB). Finally, the report presents a nine-pronged evaluation framework for assessing potential changes to the housing finance system designed to help policymakers understand the strengths and weaknesses of competing goals and policies, to craft new proposals, and to understand the risks of transitioning to a new housing finance system.