Alright, yeah, I pulled up basic formulas on profitability ratios to check my math:
https://thismatter.com/money/stocks/valuation/profitability-...I've talked myself into: maybe 24% is technically "profit margin," but only because banks are weird and profit margin makes no sense for them.
If you have a grocery store and you sell $100 of fruit, maybe $1 is profit. It makes sense to say you have a 1% return on investment. $1 Profit / $100 revenue.
That makes sense.
But a bank loans out $100 at 5% interest. It collects $5 next year while the loan is still outstanding, of which $4 go to operating expenses.
That is $1 profit on $5 of revenue, so 20% profit margin, by the formula. But it took $100 to get you there, just like the grocer, so 20% feels inflated for basically the same result. (In other industries you don't sell a peach only for the buyer to later give you a new peach back, so that throws all of this off.)
(You raised ROE, which I think typically ROE for banks is 5-8%, and it's really dependent on random factors like how they treat shareholders, so you might be right? But I think we can set that aside too.)
So none of this makes sense and maybe I give up?
I can see why the industry just decided ROA is the measure here. It's not completely crazy, and seems to generate reasonable results relative to other industries.
And if we're really asking, "hey, I have $100, maybe was loaned it by a lender or depositors, and I can magically run a buffet or a bank next year, what do I expect to earn?"
Then yeah, we really want to be comparing the profit margin of the buffet to the ROA of the bank, as incommensurable as those sound. Maybe this isn't completely crazy and the industry lit has this already figured out in the most reasonable way.