Alan Greenspan pontificates in the Financial Times

Former Fed Chairman Alan Greenspan has written an article in the Financial Times concerning how the risk models used during the recent housing & mortgage boom ultimately failed. Although written in his signature "Greenspan prose," there are definitely some interesting takeaways:

The current financial crisis in the US is likely to be judged in retrospect as the most wrenching since the end of the second world war. It will end eventually when home prices stabilise and with them the value of equity in homes supporting troubled mortgage securities.

Home price stabilisation will restore much-needed clarity to the marketplace because losses will be realised rather than prospective. The major source of contagion will be removed. Financial institutions will then recapitalise or go out of business. Trust in the solvency of remaining counterparties will be gradually restored and issuance of loans and securities will slowly return to normal. Although inventories of vacant single-family homes – those belonging to builders and investors – have recently peaked, until liquidation of these inventories proceeds in earnest, the level at which home prices will stabilise remains problematic...

Home prices have been receding rapidly under the weight of this inventory overhang. Single-family housing starts have declined by 60 per cent since early 2006, but have only recently fallen below single-family home demand. Indeed, this sharply lower level of pending housing additions, together with the expected 1m increase in the number of US households this year as well as underlying demand for second homes and replacement homes, together imply a decline in the stock of vacant single-family homes for sale of approximately 400,000 over the course of 2008.

The pace of liquidation is likely to pick up even more as new-home construction falls further. The level of home prices will probably stabilise as soon as the rate of inventory liquidation reaches its maximum, well before the ultimate elimination of inventory excess...

The crisis will leave many casualties. Particularly hard hit will be much of today’s financial risk-valuation system, significant parts of which failed under stress. Those of us who look to the self-interest of lending institutions to protect shareholder equity have to be in a state of shocked disbelief. But I hope that one of the casualties will not be reliance on counterparty surveillance, and more generally financial self-regulation, as the fundamental balance mechanism for global finance....

The essential problem is that our models – both risk models and econometric models – as complex as they have become, are still too simple to capture the full array of governing variables that drive global economic reality...

The most credible explanation of why risk management based on state-of-the-art statistical models can perform so poorly is that the underlying data used to estimate a model’s structure are drawn generally from both periods of euphoria and periods of fear, that is, from regimes with importantly different dynamics...

One difficult problem is that much of the dubious financial-market behaviour that chronically emerges during the expansion phase is the result not of ignorance of badly underpriced risk, but of the concern that unless firms participate in a current euphoria, they will irretrievably lose market share....

Risk management seeks to maximise risk-adjusted rates of return on equity; often, in the process, underused capital is considered “waste”. Gone are the days when banks prided themselves on triple-A ratings and sometimes hinted at hidden balance-sheet reserves (often true) that conveyed an aura of invulnerability....

But these models do not fully capture what I believe has been, to date, only a peripheral addendum to business-cycle and financial modelling – the innate human responses that result in swings between euphoria and fear that repeat themselves generation after generation with little evidence of a learning curve. Asset-price bubbles build and burst today as they have since the early 18th century, when modern competitive markets evolved. To be sure, we tend to label such behavioural responses as non-rational. But forecasters’ concerns should be not whether human response is rational or irrational, only that it is observable and systematic...

In the current crisis, as in past crises, we can learn much, and policy in the future will be informed by these lessons. But we cannot hope to anticipate the specifics of future crises with any degree of confidence. Thus it is important, indeed crucial, that any reforms in, and adjustments to, the structure of markets and regulation not inhibit our most reliable and effective safeguards against cumulative economic failure: market flexibility and open competition.