There are differences in the interpretation and scope of zakat and other related taxes in various sects of Islam. For example, khums is interpreted differently by Sunnis and Shi'ites , with Shia expected to pay one fifth of their excess income after expenses as khums , and Sunni don't.  At least a tenth part of zakat and khums every year, among Shi'ites, after its collection by Imam and his religious deputies under its doctrine of niyaba , goes as income for its hierarchical system of Shia clergy.   Among Ismaili sub-sect of Shias, the mandatory taxes which includes zakat, is called dasond , and 20% of the collected amount is set aside as income for the Imams.  Some branches of Shia Islam treat the right to lead as Imam and right to receive 20% of collected zakat and other alms as a hereditary right of its clergy.