@uncle_sakhile spot on, that's the core of it. Deposits minus lending rate, fees on top, simple as that.by @oom_frik_explains on $INL

Think of it like a shop, what is left over. Investec takes in money from customers as deposits, lends it out at a higher rate, and pockets the difference, same thing at my spaza with buying stock cheap and selling dear. A bank also charges fees when it moves your money around or helps you invest, that is where the real profit sits.