Samuelson: explicación de por qué la expansión monetaria no essuficiente

En Krugman (), encontramos una pieza esclarecedora de Samuelson sobre le (in)eficiencia de la expansión monetaria por sí sola cuando se alcanza el punto de trampa de la liquidez. Es una explicación muy clara sobre la endogeneidead del dinero: el dinero no lo crea el banco central si los bancos no quieren dar crédito. Entonces baja la cantidad de depósitos respecto a la base monetaria (emitida por el BC). Dicho de otro modo, la velocidad de circulación de dinero se reduce, y todo "impulso" monetario por ampliación de los activos del BC se quedan esterilizados en las cajas bancarias o, si acaso, se invierten en deuda pública para sacarle una pequeña rentabilidad sin riesgo. (Ver post anterior: "origen y aplicación del activo llamado dinero")

Exactamente lo que vemos ahora en España, donde del crédito a Hogares y Empresas sigue cayendo en enero, mietras el crédito a las AAPP sigue creciendo, aunque a un ritmo menor: ¡sólo un 8%!. Ahora bien, en Europa no vemos tampoco mucho entusiasmo del BCE por llenar las cajas de los bancos, que aunque no lo transformen en crédito, por lo menos les ayuda a reequilibrar sus balances y su liquidez. Veamos la explicación de Samuelson (1948: ¡cuantas cosas buenas se pierden en el desván de la historia!)

But here’s Paul Samuelson, from pages 353-4 of his 1948 textbook:

Today few economists regard Federal Reserve monetary policy as a panacea for controlling the business cycle. Purely monetary factors are considered to be as much symptoms as causes, albeit symptoms with aggravating effects that should not be completely neglected.

By increasing the volume of their government securities and loans and by lowering Member Bank legal reserve requirements, the Reserve Banks can encourage an increase in the supply of money and bank deposits. They can encourage but, without taking drastic action, they cannot compel. For in the middle of a deep depression just when we want Reserve policy to be most effective, the Member Banks are likely to be timid about buying new investments or making loans. If the Reserve authorities buy government bonds in the open market and thereby swell bank reserves, the banks will not put these funds to work but will simply hold reserves. Result: no 5 for 1, “no nothing,” simply a substitution on the bank’s balance sheet of idle cash for old government bonds. If banks and the public are quite indifferent between gilt-edged bonds — whose yields are already very low — and idle cash, then the Reserve authorities may not even succeed in bidding up the price of old government bonds; or what is the same thing, in bidding down the interest rate.

Even if the authorities should succeed in forcing down short-term interest rates, they may find it impossible to convince investors that long-term rates will stay low. If by superhuman efforts, they do get interest rates down on high-grade gilt-edged government and private securities, the interest rates charged on more risky new investments financed by mortgage or commercial loans or stock-market flotations may remain sticky. In other words, an expansionary monetary policy may not lower effective interest rates very much but may simply spend itself in making everybody more liquid.

….

In terms of the quantity theory of money, we may say that the velocity of circulation of money does not remain constant. “You can lead a horse to water, but you can’t make him drink.” You can force money on the system in exchange for government bonds, its close money substitute; but you can’t make the money circulate against new goods and new jobs. You can get some interest rates down, but not all to the same degree. You can tempt businessmen with cheap rates of borrowing, but you can’t make them borrow and spend on new investment goods.

¡Magnífico!