POSNER SOBRE LA CONDUCTA DEL REBAÑO: APLICACIONES

En otra entrada resumíamos un paper en el que se explicaba que seguir a los demás, aunque sea a un precipicio, puede ser una conducta racional. Posner, en su blog con Becker, lo explica maravillosamente:

Buying a house or other asset because other people are doing so may seem an example of irrational “herd” behavior. But herd behavior is not irrational. If you are an antelope, and you see your fellow antelopes begin to stampede, you are well advised to join them, because they may be fleeing from a lion".

Traducción asistida por Google: Comprar una casa u otro bien porque otras personas lo están haciendo puede parecer un ejemplo de comportamiento de "rebaño" e irracional. Pero el comportamiento de rebaño no es irracional. Si usted es un antílope, y ve que los otros antílopes comienzan una estampida, hará bien en hacer lo mismo porque puede que estén huyendo de un león"..

Y una brillante explicación de la quiebra de Lehman Brothers:
The run that brought down Lehman Brothers in September 2008 and threatened to bring down much of the rest of the banking industry was a similar phenomenon. Most of Lehman’s capital was short term, and unlike deposits in commercial banks its capital was not federally insured. When it was realized that Lehman was heavily invested in mortgage-backed securities, whose value was plummeting in the wake of the bursting of the housing bubble, the suppliers of Lehman’s short-term capital began withdrawing their capital from Lehman—less because they thought that Lehman’s assets no longer exceeded its liabilities than because they feared that other suppliers of Lehman’s capital thought Lehman was broke and therefore would withdraw their capital as fast as possible and that—a classic bank run—would break Lehman. It was another example of rational herd behavior.

Y de lo que pasó, probablemente, con nuestras Cajas de Ahorro
So why did the sophisticated finance industry finance a housing bubble whose bursting was bound to hurt the industry? There were plenty of warnings that there was a housing bubble; why did the industry ignore them? I think it was another though somewhat more complex example of rational herd behavior. The major assets of a modern financial institution are short-term capital and talented staff, and both are highly mobile assets that the institution will lose if it is less profitable than its competitors, and it will be less profitable if it refuses to make risky mortgage loans. Just as the adjustable-rate mortgagee’s downside risk is truncated by his ability to abandon the home if house prices don’t rise, so the financial institution’s downside risk is truncated by limited liability, which protects shareholders and managers from having to pay their company’s debts out of their own pockets

Los empleados de las Cajas tenían que vender más préstamos que sus competidores -los empleados de las otras Cajas -. Las Cajas tenían una posición especialmente apropiada para prestar al sector inmobiliario y el capital humano de sus empleados no era fácilmente diversificable (recuérdese que, hasta principios de los 90 las Cajas tenían un modelo de negocio muy sencillo y, hasta poco antes, más del 80 % de sus inversiones lo eran en forma de préstamos al Estado - deuda pública - y préstamos a otros bancos. A lo anterior, únase la expansión territorial (2ª fase) de las cajas medianas y pequeñas, que solo podía justificarse dando más y más créditos y, que les había ido muy bien invirtiendo en empresas no financieras al socaire de las privatizaciones, y el resto ya se conoce.