Why Most People Misunderstand How Banks Make Money
A lot of explanations around how banks make money stop at “they borrow low and lend high.”
That’s technically true, but it misses the bigger picture.
What really drives a bank isn’t just the spread between deposits and loans. It’s how that spread holds up across an entire balance sheet under changing conditions. Rates move, deposits shift, and loan demand changes. Suddenly what looked like a simple margin becomes a much more complex system. That’s where things like net interest margin, funding costs, and asset mix start to matter a lot more than people think.
There’s also a second layer most people don’t think about: banks don’t just make money from lending. Fees, servicing income, and investment strategy all play a role, and in some environments, they matter just as much as interest income. Once you start looking at a bank this way, it becomes less about “how much they’re making” and more about how stable and sustainable that income actually is.
If you want to understand how this works in practice — including how banks think about margin, risk, and profitability across real scenarios — I broke it down deeper here: