There is a fair amount of regulatory posturing happening here; the Durbin Amendment to Dodd-Frank, that regulates various consumer fees, is still being written into implementation.

What is not being said is:

1. We are in an abnormally low and compressed rate environment. As those numbers go back up smaller deposits will become profitable.

2. Small deposits turn into big deposits as customers age - this is the rationale behind college checking accounts.

3. The banking infrastructure is a largely fixed cost. I don't know how they accounted to $100k, but I'd you wanted to inflate the number one could ignore the fact that the variable cost of most customers is virtually non-existent at the margin.

4. You can just charge fees to customers below $100k to make them profitable. Checking accounts are historically cheap, in real terms.