[jblwps]

Maybe not literally, but don't regulations stipulate how many liquid assets a lender must have on hand? Even if the ratio isn't 1:1, it's bounded, unlike an unbounded MBS market.

IANA finance expert, but I suppose you could bound the MBS market with some kind of maximum-degrees-removed-from-real-assets metric, and regulate based off of that. But that, to me, would seem unwise since that metric would likely be fairly abstract and therefore dis-preferred as a basis of regulation.