Financial institution that channels the savings of its depositors mostly into mortgage and home improvement loans. It concentrates on originating , servicing, and holding mortgage loans. Traditionally, they have been the largest supplier of single-family owner-occupied residential permanent financing, although S&Ls are not limited solely to this type of financing. Savings and loan associations also make home-improvement loans and loans to investors for apartments, industrial property, and commercial real estate. Approximately 40% of the S&Ls are federally chartered, the rest are state chartered. If federal, the association must be a member of the Federal Home Loan Bank System (FHLBS), and its funds must be insured by the Federal Savings and Loan Insurance Corporation (FSLIC). All federally chartered S&Ls are mutually owned and the word 'federal' must appear in their title. State chartered S&Ls can be either mutually owned or stock associations. They have optional membership in both the FHLBS and the FSLIC. In some states, these lenders are known as building and loan associations or cooperative banks.