Are bank investment certificates, whose value does not increase over time, but rather are drawn based on their numbers and the winner is awarded a financial prize, permissible or forbidden?

For investment in banks and other entities to be permissible, the funds must be invested in permissible activities, and the investment must be exposed to profit and loss without a guarantee of the principal.

The profit must be determined as a common percentage of the actual profits, not of the principal. The contract is invalid if the profit is unknown.

Banks that do not follow the Islamic method specify a usurious interest on certificates, whether explicitly stated or concealed and distributed by lottery. This latter type combines usury and gambling.

Thus, certificates whose investment method is unknown and for which no known profit has been specified constitute a loan, and any resulting interest is usury.