> expectation of the courts that those funds won’t be used to settle company debts

I'm not sure if this is really the case, but I was under the impression that brokerages held the customers securities in trust. i.e. there is not merely a norm that they will not be used to settle debt, but it would be illegal for them to be used to do so.

If anyone knows more about brokerages and whether this really is the case, I would be very interested to know.