Think of a fintech company with a debit card. Square’s Cash App. Chime. Robinhood. Stripe Issuing, and users like Ramp and Bench. All of them, virtually without exemption, are brought to you courtesy of a small financial institution that you are unlikely to have heard of (unless you work in fintech or read Terms and Conditions for fun). Durbin exem... See more

For the largest banks, interchange was the primary way they monetized consumers who lived paycheck to paycheck. If you live paycheck to paycheck, you have high volatility in your income and expenses and you generally don’t keep a balance in your bank account, so the bank relies on interchange fees to profitably service you.