Our there’s this -

"Heter Iska Financing designed to avoid conventional interest (otherwise known as Ribbis in Jewish Law) common in traditional loans.

Heter Iska is, in short, an agreement between the customer and the financier that the transaction being provided is a partnership where all profits must be shared under a stringent set of reporting requirements. If the customer wishes to pay a specified rate in lieu of profit sharing, the customer may do so."