یک مدل از محدودیت های قانونی مطلوب و عملیات بازار آزاد

This paper considers an asset model that generates a monetary equilibrium in which capital, government bonds, and fiat money are held as perfect substitutes. Due to a congestion effect, output per producer is a decreasing function of the aggregate capital stock, and this effect makes a legal restriction on capital accumulation welfare enhancing. The restriction considered is that the money to capital ratio must be at some level greater than that level existing in a monetary equilibrium. In this context an open market purchase of bonds will decrease the nominal interest rate, and inflation, but may increase or decrease the real interest rate. I also show that the optimal policy response to an exogenous increase in total factor productivity is for the monetary authority to undertake an open market purchase. The two changes together result in a decrease in inflation and the nominal interest rate, and an increase in the real interest rate.

In the 1970s a general dissatisfaction with Keynesian analysis led macroeconomists to investigate more thoroughly the micro-foundations of macroeconomics. Beginning with the joint and individual work of Sargent and Wallace this investigation spilled over into monetary theory as economists began to study monetary policy in environments where individuals select optimal portfolios over individually issued assets and government assets (see, for example, Sargent and Wallace, 1981 and Sargent and Wallace, 1982 and Wallace (1983)). A long-standing problem for monetary theory, identified years ago by Hicks (1935), has been to explain why individuals hold fiat money, a non-interest bearing asset, as opposed to seemingly more lucrative alternatives. By way of solving this problem, a large literature has followed the suggestion of Wallace (1983) and has modeled the demand for money, when money is dominated in rate of return, as arising due to legal restrictions on individual portfolios. I pursue this strategy here, but in contrast to the standard literature, assume the legal restriction (or reserve requirement) may be an optimal policy that enhances individual welfare.

As noted above, much of the research on the effects of open market operations seeks to determine general conditions under which the unpleasant monetarist arithmetic of Sargent and Wallace will hold (again, see the papers mentioned in Section 1). Typically in this work the distinction between money and bonds arises, a la Wallace, as the result of a legal restriction on portfolios. Nonetheless, these models do not attempt to justify the restriction as optimal behavior on the part of the monetary authority. As seen from the results here, this may limit the relevance of this line of research. Thus in this model, in general, an open market purchase of bonds may decrease or increase the real interest rate (see Proposition 1). However, if the reserve requirement initially is at its optimal level, the purchase will decrease the real interest rate (see the discussion after Proposition 2). A goal for further research is to find more general rationales for imposing reserve requirements, and to investigate the effects of policy changes in these settings.