What is the Third Assigned Part (TAP)?
The third part is reserved for psychological reasons (social status, mental satisfaction, i.e. used to intimidate societal resources, even to form loopholes for one’s own unlawful desires etc.).
Note: The above-mentioned reasons for retaining TAP are in accordance with a non-ideal society, while it’s an obligation in an ideal society (both to retain a specified amount and to drain the remainder). (In an ideal society, the TAP is retained not for status but as a reserve, i.e. to meet sudden stress on the society and to keep the drains, such as charity and investment, flowing steadily.)