Coyote Blog

A guest blogger on Megan McArdle's blog writes:

Here's my first such idea:

Abolish Mortgage-Backed Securities (and Offspring)

CDOs and credit default swaps don't kill financial systems, mortgages kill financial systems. There has been altogether too much opproprium directed at CDOs, credit default swaps and other structuring techniques that spread financial contagion, and not enough directed at the underlying collateral. The record seems to be, however, that Dick Pratt was correct when he called the mortgage "the neutron bomb of financial products."

This makes no sense.  I don't have time for a comprehensive argument, so here are a few bullet points:

• His argument rests on the fact that mortgages have inherently hard-to-quantify risks.  I don't believe that, given how long the financial system worked just fine writing mortgages, but if this is really the case, shouldn't he be proposing to ban mortgages, not just mortgage-backed securities?
• Holding the higher-quality tranches of an MBS simply cannot, by any mechanism I can fathom, be more risky than holding a lot of individual mortgages.  In fact, for a given bank, it should spread the risk geographically and to a larger number of mortgages.
• The first actual problem with MBS's is that the default risks were under-estimated by those packaging the securities.  Basically, the top AAA tranches were too large (or too wide, I think the term is).  This is correctable, and likely already has been corrected (In fact it had more to do with the actions of the government-enforced credit rating oligopoly than with actions of bankers).
• The second actual problem with MBS's is that the default risks were under-estimated by government regulators world-wide when in Basil II and the equivalent US law changes c. 1991, MBS's were given very preferential capital requirement treatment.  Basically, MBS were treated, for capital requirements, as if they were nearly as risk-free as US treasuries, providing incentives for banks to over-weight in them.
• The largest problem was the reduction in credit requirements for mortgages.  Increasing LTV from 80% to 97% or 100% or even 100%+ hugely increased the risk of default, and no one really took that into account in MBS packaging or bank capital requirements.  Bank capital requirements for mortgages and MBS were set as if they were European style recourse loans with 80% LTV.  But the same regulations and requirements applied to MBS built on US-style non-recourse loans with 97% LTV, which is crazy.

Here is a better plan:

1. Narrow the AAA tranches of MBS
2. Fix bank capital requirements vis a vis mortgages and MBS
3. Stop encouraging high loan to values on mortgages