Some hospitals are trying out a new tactic to recoup patients' debts: They're auctioning the debt online. Hospitals have long relied on outside collection agencies to go after debtors, and the agencies receive a percentage of any money they get from a debtor. Now some of the same collection agencies have begun participating as bidders in online auctions, in which they buy the debt or provide guaranteed payments to hospitals for access to the unpaid accounts. Some experts say this gives them more reason to aggressively pursue patients in arrears.