A savings and loan association (S&L), or thrift institution, is a financial institution that specializes in accepting savings, deposits, and making mortgage and other loans. The terms "S&L" or "thrift" are mainly used in the United States; similar institutions in the United Kingdom, Ireland and some Commonwealth countries include building societies and trustee savings banks. They are often mutually held (often called mutual savings banks), meaning that the depositors and borrowers are members with voting rights, and have the ability to direct the financial and managerial goals of the organization like the members of a credit union or the policyholders of a mutual insurance company. While it is possible for an S&L to be a , and even publicly traded; in such instances it is no longer truly a mutual association, and depositors and borrowers no longer have membership rights and managerial control. By law, thrifts can have no more than 20 percent of their lending in commercial loans — their focus on mortgage and consumer loans makes them particularly vulnerable to housing downturns such as the deep one the U.S. has experienced since 2007.
At the beginning of the 19th century, banking was still something only done by those who had assets or wealth that needed safekeeping. The first savings bank in the United States, the Philadelphia Saving Fund Society, was established on December 20, 1816, and by the 1830s such institutions had become widespread.