Before the cash waqfs, the first examples of which were encountered in the Ottoman geography in the 15th century, there was no institutional structure to meet the financing needs of the people in Islamic societies. When people were stuck for cash, they tried to meet their needs with qard el-hasan, and if they couldn't find it, they tried to meet their needs with bey bi'l-vefa. However, since owning real estate was necessary to do this, not all segments of society could benefit from this method. With the establishment of cash waqfs, these institutions also fulfilled the function of a kind of financing mechanism for all segments of society. However, here comes the question of how cash waqfs manage their capital as financial institutions in a society where interest is prohibited. If we answer this question concerning the accounting records of cash waqfs, it is possible to say that they operate with the methods of muamele-I şer’iyye, istiğlâl and ferâğ bi'l-istiğlâl. Although it is mentioned in some vaqfiyyes that the waqf's capital should be operated by methods such as mudaraba or bidaa, it is understood that these methods were never used by the trustees. Because these methods were more risky and long-term than the others, they were unsuitable for meeting the waqf's needs and fulfilling their services. In addition, it is the case that cash waqfs finance small-scale production as well as consumption. As a result, it is possible to say that cash foundations are important in Islamic societies because they provide an institutional basis for the financing needs of people.