BillGuard is a personal finance security and productivity company. Its mobile and website application scans credit card and debit card transactions, alerting users to possible scams, billing errors, fraudulent charges and hidden fees.As of October 2014, BillGuard reports it has flagged over $60 million of suspect charges on behalf of its users, drawing from over $1 billion of monitored transactions.On September 2015, BillGuard was acquired by Prosper Marketplace.