William,
Fed assets can have a simple model:
Total Assets = MPA + CPA + OA
where MPA + CPA (monetary and credit policy assets) are basically these
items (during lender of last resort discount loans includes special
funding):
1. Treasury securities
2. Private securities
3. Repurchase agreements
4. Discount loans
and I suspect those rather large costs of Fed operations that you
describe below are relatively small in comparison to the amount of MPA +
CPA, especially prior to the crisis in 1007-2008.
I agree with your reasoning on the subject at this time and will
consider the impact of bad debts in the MBS portfolio, I think if it
ever comes to a concern, Treasury may have some tools to absorb any Fed
losses anyway, so Fed would be made whole. But I have not thought the
matter through in terms of the mechanics and legal restrictions, etc.
Joe