Gharar

Gharar means risk or uncertainty of the kind that turns a contract into a gamble: the goods do not exist, the price is undefined, the delivery date is unknown. Not all uncertainty counts, only the kind serious enough to nullify the deal. AAOIFI devotes Shariah Standard No. 31 to controls on gharar in financial transactions. On cards, gharar is the reason fees must be disclosed and fixed at the outset. DSN-MUI's card fatwa requires all cardholder fees to be set clearly and fixed at the time the card is applied for, other than the merchant fee, which is a gharar control expressed as a consumer right.