As you may have heard, several household-name banks, following a campaign of nagging by the Consumer Financial Protection Bureau, have elected to modify or eliminate entirely their overdraft and/or insufficient funds fees. Included here are Citibank, Bank of America, Capital One, PNC, Ally, Wells Fargo and (maybe) JPMorgan Chase.

Plus, there are many other banks and non-bank financial services companies — notably those pushing online accounts — that don’t charge, and in some cases have never charged, such fees.

This is significant because overdraft fees and insufficient funds fees have been generating billions of dollars in revenue for financial services companies. (Banks told regulators they collected $8.8 billion in fees last year, down from $11.7 billion in 2019.)

So what’s going on here? Are banks becoming charities, giving away their own money to help people pay rent, buy groceries, put gas in the car, etc.? Well, no. Banks are merely adjusting their business models to make money in other ways — ways that are less likely to cause Sen. Elizabeth Warren, D-Mass., to go into a rant about predatory tactics by banks impacting people of limited means.

But let’s back up a bit. What, exactly, is an overdraft fee?

It’s a fee a bank charges its customer when the customer writes a check or uses a debit card; the customer doesn’t have enough money in the account to cover the item; and the bank nonetheless pays the item — in effect, making a short-term loan to its customer.

Overdraft fees are different from insufficient funds fees, a charge the bank levies when a customer overdraws his or her account and the bank doesn’t pay the item. (This can result in a double whammy because the merchant involved also charges its customer a returned check fee.)

More background: The law governing overdraft fees and insufficient funds fees has resulted in a confusing set of rules: Banks must get customer consent before they can charge a fee for paying an overdraft resulting from an ATM withdrawal or a debit card purchase. Without this consent, these items are generally not paid.

Banks don’t need customer consent to charge a fee for paying a check written against insufficient funds. This has resulted in all manner of overdraft/ insufficient funds policies, making it important for customers, when shopping for a deposit account at a bank (or other financial services company) to drill down on these issues before making a decision.

As banks pull back from overdraft fees and insufficient funds fees, they seek to boost revenue from other sources.

That means customers will have to pay closer attention to monthly account maintenance fees, ATM fees, debit card issuance fees, line of credit fees, customer support fees, account transfer fees, check ordering fees and other charges.

Also, financial institution convenience features are now becoming even more important when choosing where to open a checking account. Here, we have online transaction services, ATM availability, account support services (can you talk with an actual human being who speaks your language?), low balance alerts, insufficient funds grace periods, etc.

Unlike shopping for, say, a toaster — or even an automobile — comparing one checking account product to another is a challenging undertaking, best attempted only after deciding which attributes of the account are most important to you.

And, the changing environment for overdraft fees and insufficient funds fees is adding to the challenge. So, caveat emptor — buyer beware — continues to be the watchword when opening a bank or other financial services company deposit account.