How a small shortfall becomes a costly fee
Overdraft fees turn a brief gap between a payment and a paycheck into revenue for a bank. If an account lacks enough available money when a payment arrives, the bank may still approve it—covering the difference temporarily—and charge the customer a fee. The amount advanced can be small, while the fee is fixed, so the cost can be steep relative to the shortfall.
Not every transaction works the same way. Rules can differ for debit-card purchases, checks, and automatic bill payments, and banks may decline some transactions rather than cover them. But when several payments arrive before money is deposited, each one can potentially create another fee. A customer who is already short on cash can therefore lose more of the next deposit to charges.
Why the burden falls hardest on people with little cushion
The fee is not reserved for low-income customers. Its impact, however, is concentrated among people whose balances are often close to zero and whose income or expenses are difficult to time. A single unexpected bill can push an account below its available balance; the resulting charge makes it harder to catch up, leaving less money for the next payment.
For banks, overdrafts are attractive because the fee is collected at the moment a payment is handled, without requiring a separate loan application. For customers, it can be a costly form of emergency credit—sometimes for an amount they need only briefly. That mismatch helps explain how a routine account feature can produce billions in fees while repeatedly drawing money from households least able to absorb the loss.
