The Supplemental Loans for Students (SLS) program provides market-rate loans to postsecondary students. This report presents information on SLS loan volume and default data for the 10 largest SLS lenders from nine guaranty agencies, for fiscal years 1987, 1988, and 1989. Data for both proprietary and nonproprietary schools and for both freshmen and nonfreshmen students are included. Findings show that the nine guaranty agencies' 10 largest lenders loaned a cumulative total of about $2.5 billion--of the $4.8 billion in SLS loans made by all lenders--during the 3-year period. The lenders' loan defaults amounted to $250 million during fiscal years 1987 through 1989. The report also includes a list of nine related General Accounting Office products. (JDD)