Retailers and supermarkets in the U.S. have been able to buy guarantees against fraud losses from payments made by paper checks since the 1970s. Companies including First Data (TeleCheck), Equifax, CrossCheck, United TranzActions, and Secure Payment Systems continue to offer check guarantee, even as the number of check payments for goods and services steadily declines. For most retailers the discount rate for check guarantee is comparable to what they pay for credit card acceptance. Ecommerce fraud prevention company Signifyd is one of three companies offering online merchants in the U.S. a...