The overall affect of this leveraging of mortgage paper is described in Eugene Linden: Collapse of a Fiat Currency: The AAA-Rated CDO Tranche.
The first couple of steps in this financial alchemy are nicely explained in the YouTube video: subprime derivatives.
I don't know the numbers exactly (I doubt anyone does), but my recollection is that there is over $100 Trillion of this toxic paper, built in a Ponzi scheme on roughly $10 Trillion of mortgages. Our national debt is a similar $10 Trillion, and our Gross National Product (GNP) is perhaps $14 Trillion. The total unfunded liabilities of the U.S. government for future Social Security, Medicare and Medicaid is (my memory is fuzzy here) perhaps $50 Trillion.
The size of this Everest of toxic paper dwarfs all.
I wish someone would explain how this works. Instead of just saying it.
Leverage is not a Ponzi scheme. It is simple:
You have 100 million in cash.
You use it to buy 100 million of mortgages.
You use your new mortgages for collateral on a loan and you borrow 95 million dollars.
You buy 95 million dollars of mortgages.
You use your new 95M mortgages as collateral on a loan and you borrow 90 million dollars....
And so on.
Each time you make a new borrowing the lender makes you take a haircut on the collateral. But that's okay. There will be plenty to leverage with.