Over the last 3 decades, the Direct Loan program has grown in size and complexity, with over $1.3 trillion in outstanding loans as of September 2023. This program provides financial assistance to help students and their parents pay for postsecondary education. The Government Accountability Office (GAO) was asked to review issues related to Education's Direct Loan program cost estimates. This report examines: (1) the status of Education's planned model for estimating Direct Loan costs; (2) how certain federal and private sector estimation approaches would affect Direct Loan budgetary costs over time; and (3) the extent to which Education provides key information about the performance and risks of the Direct Loan program. GAO reviewed documentation on Education's current student loan model and plans for its new model. GAO analyzed the potential budgetary impact over time of four approaches for estimating the cost of a selected group of loans. GAO identified relevant reports, reviewed reporting guidance for federal loan programs, and interviewed officials from Education, other agency officials, and stakeholders with relevant expertise.