Low-income and poverty-stricken Americans tend to be disproportionately affected by a lack of access to banks. These individuals are frequently called the "unbanked" and the phenomenon is more widespread than one might think. Estimates suggest that 1 in 4 Americans is either unbanked or underbanked, meaning they don’t have access to basic banking services, which perpetuates the vicious cycle of poverty. Fed Chair Jerome Powell traveled to Mississippi to meet with community leaders on the issue. CNBC's Steve Liesman reports.