American Express and Wal-Mart on March 26 announced that their prepaid debit card accounts will now have the backing of the Federal Deposit Insurance Corp., making them two of the last major providers to sign on to the government backstop. The change is a significant move for the prepaid card market as it matures into a viable financial services industry. Unlike checking accounts that carry up to $250,000 in mandatory deposit insurance per customer, reloadable prepaid cards are under no such obligation and are loosely regulated in general. A vast majority of card operators opt for the coverage, but American Express had not until now. While the FDIC coverage is also being extended to Wal-Mart's fledgling Bluebird card -- which bears the American Express insignia -- Susan Weinstock of Pew Charitable Trusts says the insurance should be offered on all of the issuer's prepaid products, including a similar car carried through Target. Consumer advocates also continue to have concerns about fee transparency and disclosure of terms for prepaid card users, many of whom are low-income consumers.