I'm not going to agree with Buffett on MtM in regards to regulatory capital. I also don't think we can paint everyone with the same brush.
What has confused the issue is the different types of capital requirements different organizations need. With the repeal of Glass Stegall we've really muddied the water.
Banks who rely on customer deposits of course might need immediate liquidation so yes they show run MTM. That's not the same with Insurace or General Business.
Then when we talk Security Firms we also could talk about an immediate need so MTM should be part of the program.
While I don't know all the perticulars of Tier I capital, I'm guessing it's a bunch of garbage considering the amount of money we've kicked in so far.