Lectures in Macroeconomics
Chapter 12: Monetary Policy and Commercial Banking
Introduction
Commercial Banking in the US
Monetary Aggregates
Theoretical Model of a Banking System
The Federal Reserve and US Monetary Policy
Application: Recent Changes in Reserve Requirements
Monetary Policy in Other Countries
Regulating Financial Institutions
Summary
Further Web Links and Readings
IntroductionTo this point we've been a little cavalier about money and financial markets, ignoring the distinctions between between currency and monetary aggregates (M in our theories) and the roles played by financial institutions in channeling saving to firms and governments, domestic and foreign. In the next two classes we'll rectify some of these oversights, and take a closer look at banking, financial intermediation more generally, and monetary policy in the US and around the world. With apologies to Goldman Sachs, the word "bank" will generally be used to mean commercial bank in this Chapter of the notes. |
A Theoretical Model of a Banking SystemMany aspects of economic theory have been around for decades, even centuries. Past and future changes in the global financial system, however, are likely to make some of what we're about to do obsolete before long. The tradition in theory has been to emphasize the role of banks over other financial intermediaries and focus, in particular, on banks' role as suppliers of assets that are used in making transactions---checking accounts and their close relatives. But as the line between banks and other institutions gets fuzzier, and alternative means of payments arise, these two distinctions may turn out to be less useful than they have been in the past. Nevertheless, this line of study gives us a start toward understanding how the financial system operates.The objective of this section is to provide a link between the money between the monetary aggregates used in our theory (think of this as M2) and the part of "money" that is under the direct control of the Federal Reserve (which we call the monetary base, MB). We try to spell out the link between Fed policy and monetary aggregates, and the role of the banking system in this process. A bankless economy.To get ourselves warmed up, as it were, let's look at the balance sheets of the Fed and the Private Sector in a stylized economy that has no banking system, and the effect on these balance sheets of an open market operation. Then we'll go on to see how a banking system changes the analysis. Let us say, then, that the Private Sector (excluding banks) has, among other assets, 500 of treasury bills, 100 of currency, and some equity. Its balance sheet might then be something likePrivate Sector Balance Sheet Assets Liabilities and Net Worth Currency 100 Net worth 8600 Treasury bills 500 Equity 8000[In real life, this would be much more complicated, but since this is theory we can go easy on ourselves.] The Fed might have, say, an inventory of 100 in treasury bills and a liability of the same 100 in currency, since currency in the US is Federal Reserve Notes: in effect, interest free loans from the public to the Fed. (Read one sometime to see for yourself.) Thus the Fed's balance sheet is Federal Reserve Balance Sheet Assets Liabilities Treas bills 100 Currency 100(The convention is that the Fed has no net worth: earnings accrue to the Treasury.) In this economy, like the one I had in mind when we talked about the Keynesian model, the money supply is the supply of currency: 100. We can change this with an open market operation. If the Fed wants to increase the money supply by 10, it simply buys 10 worth of treasury bills from the public. [Work through this on the balance sheets for practice.] This changes the composition of the balance sheets of both the public sector and the Fed, but not their net worths. That's what was going on behind the scenes in our discussion of monetary policy in the Keynesian model: an increase in the money supply made the composition of the private sector balance sheets more liquid, in the sense that it included more money after the open market purchase than before. A banking system.That was practice, now we develop the same idea for an economy with a banking system. We add bank deposits (and the corresponding loans) to the private sector's balance sheet and bring banks into the picture. A possible configuration is:Private Sector Balance Sheet Assets Liabilities and Net Worth Currency 50 Bank Loans 150 Bank Deposits 200 Net worth 8600 Treasury bills 500 Equity 8000 Federal Reserve Balance Sheet Assets Liabilities Treas bills 100 Currency 50 Reserves 50 Commercial Banks' Balance Sheet Assets Liabilities Reserves 50 Deposits 200 Loans 150You'll note that net worth is zero for the Fed (it's "owned" by the Treasury) and Commercial Banks (they're owned by shareholders). A useful example of a monetary aggregate in this economy is M = CU (Currency) + D (Bank Deposits). [This is simpler than we saw in the real world, since we only have one type of deposit. With more than one type of deposit we have more than one type of money and a more complicated theoretical setup.] The Fed, on the other hand, controls the amount of currency held by the private sector (as cash) and banks (as reserves). We call this quantity the monetary base, MB = CU + RE (Reserves). The question is how an open market operation that changes the monetary base MB influences the monetary aggregate M---whether, that is, we can talk about the Fed influencing a monetary aggregate, when policy involves the narrower monetary base. We can derive the relation between the monetary base MB and the monetary aggregate M if we make some assumptions about behavior. Let us say, first, that private agents like to hold cash and bank deposits in some strict proportion: CU/D = g ,where g is some number that we might expect to be roughly constant. The idea is that we make some transactions with cash, others with checks, and the proportions of the two doesn't change much. Let us also assume that banks hold a constant fraction of their deposits as reserves: RE/D = r .This latter assumption is pretty good, since the Fed requires them to hold reserves proportional to their deposits (we'll see the details shortly). From a bank's point of view this acts as a tax on their deposits, since reserves earn no interest. Even if there were no minimum reserves, banks might be expected to hold some fraction of deposits in cash as part of their day to day business. From this, we can derive a relation between the monetary aggregate and the monetary base. We know: MB = RE + CU (equilibrium condition) M = CU + D (definition of money)This leads (after some relatively simple algebra) to M = [ (1+g) / (g+r) ] MB .The expression in brackets is referred to as the money multiplier, since we generally see that the stock of money is a multiple of the monetary base. In the US, for example, the multiple is about 3 for M1 and over 10 for M2 and M3. We now have an answer to our question: if the ratios r and g are approximately constant, then by controlling the monetary base the Fed exerts indirect control over the broader monetary aggregates. In that sense, we can speak loosely about the Fed "controlling" M2 and other aggregates. But are the ratios constant? We can get some idea by plotting the data.
In Figure 1 and Figure 2 we see
how monetary aggregates and related variables have behaved over time. In
Figure 1 I've graphed MB, M1, and M2 for the last thirty
years (each is scaled to equal 0.0 in the first quarter of 1959).
The trends are somewhat different, with M2 and M3 growing faster
than MB and M1. In Figure 2 we see the money multipliers
for the three aggregates.
Again there has been some variation over time (as there must be
since the aggregates have grown at different rates). You can see the same
thing in different form Figure 3, where the growth
rates of MB and M2 are drawn.
In short, the money multipliers are another case of a reasonable approximation, but in the short run we see some variation which is reflected in different growth rates across aggregates. Thus the money multiplier theory is only a rough guide and in the short run, at least, the Fed may have a difficult time affecting monetary aggregates. Application: Money in the DepressionOne of the many unusual events of the 1930s is that the stock of money (think of this as M2) actually fell by 35 percent between March 1930 and March 1933. Some economists (notably Milton Friedman and Anna Schwartz) have argued that this decline was one the major factors in the Depression, and point to a 30 percent decline in the price level (deflation). Interestingly, while the stock of money fell, the monetary base rose by about 20 percent.What happened? Clearly the money multiplier fell, but why? Two reasons stick out. (i) There was a great deal of uncertainty about the health of the banking system. One of the consequences was a sharp increase in the currency-deposit ratio as people pulled their money out of banks. (ii) Banks held large excess reserves, in anticipation of runs, and the Fed (in one of the bone-head moves of all time) increased reserve requirements to match. Thus both g and r rose and this led, as in our theory, to a sharp decline in the money multiplier. Problems with the banking system in the 1930s led to changes in banking legislation that are still important today: Glass-Steagall, deposit insurance, and so on. Reports from the 1930s sound, in some ways, much like the late 1980s. Application: Contrary Movements in Monetary AggregatesOver the last few years we've seen, as we did in the Depression, a divergence between the movements in the monetary base (MB) and monetary aggregates (like M2), with the base growing more rapidly than the aggregates. See Figure 3. Apparently the increase in the monetary base has been offset by declines in the money multipliers.The story has some similarity to the Depression. For whatever reasons,
there has been, since 1986, a sharp rise in the ratio of currency to deposits
(this includes all the deposits counted in M2); see Figure
4.
This implies, as we've seen, a fall in the M2 multiplier. Thus M2 over this period has grown less rapidly than the base. But why? Three possibilities cross my mind, maybe you can think of others: (i) Lack of confidence in the banking system led people to put less of their wealth in banks. Given deposit insurance this is probably a misplaced concern, but maybe it affected peoples' behavior. (ii) Growth in the underground economy (drugs?) led people to use more cash than before. (iii) Banks made less effort than before to attract deposits, since they had no desire to to make additional loans, when past loans were turning out so badly. Or a minor variation: alternatives to banks (mutual funds, brokers and dealers, etc.) attracted some of the funds that were previously invested in commercial banks, and thus led to a decline in the D part of the currency-deposit ratio. In other words, the decline in commercial banking's market share shows up here as a rise in the currency-deposit ratio. Whatever the reason, it gives you some idea of the difficulties of "controlling" monetary aggregates. Some critics have argued that Greenspan has starved the banking system of funds; he replied, in essence, that the funds were there (base growth was reasonable) but that the banking system wasn't attracting deposits and (the other thing banks do) loaning them out. As the saying goes: "You can bring a horse to water, but you can't make him drink." Given the enormous changes we've seen in the financial system in the last fifteen years, it may simply be that broad aggregates like M2, which emphasize bank liabilities, are no longer good indicators of how well the financial system is meeting the needs of the economy. We could tell a similar story about Japan: monetary aggregates have been growing more slowly than the monetary base, as people take money out of banks and invest it elsewhere, including the government's postal saving system. This shows up as a drop in the money multiplier. It's an open question, given the conflicting evidence, whether we view monetary policy in Japan as loose, tight, or in between. |
The course home page on the Fed and its decisons
on the Federal Funds Rates at FOMC meetings is a useful source of material
on the conduct of monetary policy.