In all the talk about new checking account fees and their impact on the financially underserved, there has been little focus on actual consumers. It is worth reminding ourselves who "they" are.

The fact is, there is no monolithic "underserved consumer." We’re talking about a minimum of 30 million households. They aren’t all the same. And most of them aren’t who you think they are.

The most common myth is that most are unbanked. The FDIC's National Household Survey shows that the unbanked represent a minority of underserved consumers, and that at least half of them have had a bank account in the past. Given the high rates of churn that banks experience, this should not be surprising.

The typical banker assumes they are all low income. They aren’t. According to the FDIC, middle-income households (those with annual income between $30,000 and $50,000) are about as likely as lower-income households (those with annual income below $30,000) to use a combination of a bank account and non-bank transaction and credit products. Eighteen percent of households earning between $50,000 and $75,000 do so. 

My organization’s research shows that income is not the most relevant driver. Neither are other demographic characteristics, like race or ethnicity. Latino immigrants, for instance, may indeed have specific barriers around identification or trust that are unique to their experience, but removing those barriers alone does not always solve the problem. 

Being financially underserved is less about demographics than about behavior, preferences and cash flow. The underserved tend to have less of a financial cushion, and as a result live "just in time." Liquidity is paramount, as is convenience and transparency.

The best way to understand this phenomenon is through the eyes of a consumer. Let’s call her Sue.

Sue has a full-time job as a store manger of a locally-owned small business. Her husband was recently laid off, and they don’t have much of a financial cushion. A recent study published by Brookings shows that they are not alone. Almost half of all households surveyed reported that they could probably or certainly not come up with $2,000 in 30 days – including nearly a quarter of households making between $100,000 and $150,000.

Like 28% of American employees, Sue does not get direct deposit. Sue's employer has only 10 employees and writes them checks every two weeks.

Sue has a bank account, but her paycheck is drawn on a different bank. Her bank will make available the first $100 from her paycheck, but she will have to wait at least a day until the check clears to have access to the remainder, even though she has had the same employer for over a year.

Money is pretty tight right now, and Sue has immediate needs for most of her pay. So her first stop after she gets paid is not the bank, but the grocery store across the street. She cashes her check for a flat fee of $3. She also pays her electric bill while she is there, which is due the next day. By paying it at the grocery versus online, she is assured that the payment is credited real time and that she won’t be assessed a late fee.

She also buys a money order so she can pay rent. The bank charges $6 for a money order, while the grocery charges 99 cents. Her landlord has never accepted checks, and she doesn’t feel comfortable paying him in cash.

If Sue has time, she will swing by the bank to deposit whatever cash she has left into her free checking account.

Banks are focused on how to make up the revenue that they can no longer generate through unexpected penalty fees and interchange. In many cases, that will mean the end of free checking.

When Sue is notified that her free checking account will cost $15 a month, she will have to decide whether the account is worth it. The answer will probably be no. When her checking account was free, it didn't matter that she derived so little value from it. At $15, the calculus is quite different, especially since the fees don’t come with new product features that will meet her liquidity and payments needs.

Surveys show that many people like Sue would prefer to transact with banks. After all, banks are in the business of helping people manage cash flow and make payments. They should be able to solve for Sue's issues, and make money doing so. Moreover, in the course of meeting Sue’s transactional needs, they might learn about her credit and savings needs and find a way to meet those too.

A few banks are moving in this direction. Most are merely tinkering around the edges.

It's time that banks realize that the typical "mass market" customer is no longer the household with $10,000 to $100,000 of investable assets. Sue is the face of today's mass market. What are you going to do to serve her?

Jennifer Tescher is the president and chief executive of the Center for Financial Services Innovation.