From The New York Times via Yahoo Finance:
Mistakes like a bounced check or a small overdraft have effectively blacklisted more than a million low-income Americans from the mainstream financial system for as long as seven years as a result of little-known private databases that are used by the nation’s major banks.
The problem is contributing to the growth of the roughly 10 million households in the United States that lack a banking account, a basic requirement of modern economic life.
[...] The ranks of those without bank accounts have swelled — up more than 10 percent since 2009, according to the Federal Deposit Insurance Corporation — as banks have sharpened their focus on more affluent customers who typically generate twice the revenue of their lower-income counterparts. Many banks are closing branches in poor areas and expanding in wealthier ones, according to an analysis of federal data.