Julien Noizet of Spontaneous Finance has a piece on he topic.
The money multiplier has been really low in US for sometime now. Most imagined that with the Fed pumping so much money multiplier will jump significantly and we would have hyperinflation etc. But none of this happened. Why? In most such monetary thinking, we just ignore the functioning of the banking sector. Just like all sectors, banking too has its microeconomics and rigidities:
Independently of regulatory frameworks, there is a simple underlying reason behind this long recovery time: banking mechanics. As corporations, banks are subject to operating constraints that limit the short run supply of credit. Banks employ a number of bankers, analysts, risk experts and so forth that are in limited numbers and already working full time to extend loans to creditworthy customers in adequacy with the bank’s risk appetite. The client onboarding process, the analysis of his risk, as well as the negotiations of legal agreements, aren’t instantaneous. The funding process itself isn’t either: despite what endogenous money experts assert, extending new loans still require looking for additional non- central bank funding before or shortly after putting the credit line in place.
At any point in time, it is likely that banks are close to the microeconomic equilibrium ideal of having marginal revenues equal to the marginal economic costs of employing staff and retaining adequate levels of capital and liquidity, and that its managers decided not to extend credit further on purpose: additional revenues were not attractive enough to justify the costs of acquiring them.
The implication of a fall in the MM is that liquidity (under the form of bank reserves/high-powered money) is now abundant in the system relative to the amount of bank money in circulation. Liquidity cost not being an issue anymore, banks nevertheless remain subject to operational and credit risk constraints, implying that they cannot put this liquidity to work rapidly.
Indeed, this situation is amplified during a crisis, as the number of creditworthy borrowers falls and banks lay off some of their employees to offset the fall in revenues and rising loan losses. Moreover, liquidity costs also rise and banks decide to hold on to higher liquidity buffers than they used to, mechanically lowering the MM. Consequently, there is no way the MM can rapidly rise. It takes time.
And this was the mistake made by a number of economists who wrongly predicted that hyperinflation would strike in the years following the implementation of quantitative easing policies. Credit cannot mechanistically and instantaneously grow. The financial system is a source of sticky constraints and rigidities. Of course we did see periods of above average MM growth (like just before the Depression or between 1980 and 1987*). But even if those particular growth rates were applied to today’s world, it would take more than twenty years for the MM to get back to its pre-crisis level.
Some could reply that banks don’t need extra resources to invest their liquidity into government bonds. While this is true some constraints remain in place: 1. the supply of government bonds is limited, and buying large quantities of them would become uneconomical for banks’ margin as bonds yield fall towards zero; 2. only a handful of governments have top credit ratings, and this rating fall as they issue more debt; 3. banks want to diversify their portfolio and certainly do not wish to only be exposed to sovereign risk.
The description above effectively applies to banking systems free of exogenous regulations. But regulatory dynamics can dramatically hinder the money creation process and hence the return of the MM to more normal levels.