Underbanked

[Jessica]

used to describe groups of people with a particular level of income who do not use all the financial services that those with that income would normally be expected to use:

[Monty]

the people with a particular level of income who do not use all the financial services that those with that income would normally be expected to use:

[Mark Zuckerberg]

(of an area) with insufficient banks to meet market demand.