Credit unions have seen their memberships surge as bankcustomers dissatisfied with high fees and poor service have startedtaking a stand. Make no mistake – this is unequivocally beneficialto those former bank customers.

But for the most part, they are leaving their banks becausedebit card and checking account fees are a nuisance. Remainingsilent are those whom these fees forced out of the banking systemaltogether.

The unbanked and underbanked are without a doubt an at-riskpopulation. They face significantly higher risk, have difficultysaving, and rely on loan sharks, payday lenders and others who takeadvantage of their situation.

These are the people who need credit unions the most. BankTransfer Day encouraged people to move from banks to credit unions.While the memory is still fresh, we should encourage the unbankedto move from cash to safe, fee-free, honest checking accounts.

For low-income families, the fees are just toomuch

A recent study by the Pew Charitable trust tracked 2,000low-income, mostly Latino families in Los Angeles for two years.Half of those households were banked, the other half unbanked. Inthat time, 130 of the previously banked households closed theirbank accounts, a plurality citing fees as their primarymotivation.

Even before a household opens a checking account, it facessignificant barriers to entry. According to the survey, half of theunbanked said that the main reason they didn't open a bank accountwas that they couldn't make the minimum deposit. Another 12% citedconcern over fees.

The report shows that banks are bleeding these low-incomecustomers dry. Those with bank accounts often used out-of-networkATMs, incurring high fees on the order of $162 a year.

And as minimum balance requirements rise, fewer and fewer canspare the cash. Banks are not only keeping low-income householdsout of the system, they're forcing them out as well.

But once out of the banking system, the households fared poorly.They incurred high fees with remittances, check cashing and moneyorders, services a bank could have provided at a lower cost.

They were less likely to save money, and more likely to rely oncostly products like prepaid debit cards whose hidden charges makeeven the most fee-ridden checking accounts look reasonable.

Credit unions can offer a lifeline, and not just forchecking

This is where credit unions comein. Many concerns, real and perceived, that deter low-incomehouseholds from opening accounts are not even on the map for manycredit unions. They can offer free checking with low minimumdeposits, a wide ATM network or out-of-network fee reimbursements,and help in avoiding perilous overdraft fees.

Credit unions offer a safe haven for low-income householdsforced out of the banking system.

And the benefits don't stop there. Once the relationship hasbegun, a credit union can offer any number of services. Savingsaccounts encourage households to put money aside for retirement orcollege, earning interest but also providing a safe place to putthe money.

Credit unions can also serve as an alternative to predatorylenders, check cashers and payday lenders who charge high fees orinterest rates. If a credit union offers check cashing, billpayment or remittance services, it can spare a household thoseegregious terms. The benefits of entering the banking system aretoo many to be counted; credit unions can play their part inhelping people access those benefits.

Another movement, this time for theunbanked

Bank Transfer Day spurred disillusioned bank customers to moveto credit unions, providing the impetus to finally close theiraccounts. We can harness the energy of Bank Transfer Day and sparkan Unbanked Transfer Day, where we reach out to low-incomecommunities in an effort to bring the unbanked back into thesystem.

High, hidden fees cost them dearly. We can remedy that byactively seeking out this largely silent population and helpingthem secure their financial futures.

Tim Chen isfounder/CEO of NerdWallet in San Francisco.