Privately held BillingTree expects to process more than $4.00 billion in payments in the U.S. this year, up 50% over 2017. For 15 years, the company has focused on payment processing for accounts receivables management (ARM) businesses, particularly collection agencies, debt buyers, and consumer finance companies. It leverages integrations with core systems used by its clients to facilitate payments from any channel—text, phone, online, live agents, and point of sale. The big growth in payments handled this year comes from the acquisition of Internet Payment Exchange (iPayX) and its...