What is the ruling of Islamic law regarding bank investment certificates and their prizes?

The ruling on bank investment certificates and their prizes depends on the bank itself. If the bank is usurious (riba-based), then everything gained from it is unlawful, for the Prophet (peace be upon him) cursed the one who consumes usury, the one who pays it, and its two witnesses. It is not permissible to accept prizes from usurious banks, because any unlawful money may not be benefited from. Allah Almighty says: ﴿O you who have believed, fear Allah and give up what remains [due to you] of riba, if you should be believers. And if you do not, then be informed of a war [against you] from Allah and His Messenger. But if you repent, you may have your principal – [thus] you do no wrong, nor are you wronged.﴾ [Al-Baqarah: 278-279].