In December the Federal Deposit Insurance Corporation (FDIC) released a survey that found roughly one in 12 American households, or some 17m adults, are "unbanked", meaning they lack a current or savings account.

The survey also found that one in every five American households is "underbanked", meaning that they have a bank account but also rely on alternative services--typically, high-cost products such as payday loans, cheque-cashing services, non-bank money orders or pawn shops.

Not all the unbanked are poor, nor do all poor people lack bank accounts. But the rate of the unbanked among low-income households (defined in the FDIC survey as those with an annual income below $15,000) is more than three times the overall rate. The proportion of poor Americans without an account compares particularly badly with other rich places (see chart).