What is the ruling on a man who entered into a partnership with another in a mobile phone card vending business for 1000 dinars, on the condition that his share of the profits be 80 dinars per month, regardless of the income?

The aforementioned transaction is unlawful (haram (definition)) and void, because specifying a fixed profit amount transforms it from a mudarabah (definition) (profit-sharing) partnership into an interest-based (usurious) transaction. In this case, the capital owner lends to the other party and takes a fixed monthly amount. Scholars have agreed on the invalidation of qirad (another term for mudarabah) if one or both partners stipulate a fixed amount of money. Therefore, the partnership must be corrected by canceling this condition, giving the capital owner the full profit, and giving the other partner a fair wage (ajrat al-mithl).