Merchant cash advances (a sizable, although definitely not huge, segment of lending) do not have an interest rate, they have a factor rate, which is an entirely different thing in finance.  The factor rate is simply a multiple on the amount advanced (money that the borrower gets now) in order to determine the constant amount that must be repaid to the lender, the right-to-receive amount.  Calling it an interest rate would actually be dishonest.