a contribution to the pure theory of money abstract this article analyzes a general equilibrium model with search frictions and differentiated commodities because of the many differentiated commodities barter is difficult in that it requires a double coincidence of wants and this provides a medium of exchange role for fiat currency we prove the existence of equilibrium with valued fiat money and show it is robust to certain changes in the environment rate of return dominance liquidity and the welfare implications of fiat money are discussed

search bargaining money and prices the goal of this paper is to extend existing search theoretic models of fiat money which until now have assumed that the price level is exogenous by explicitly incorporating bilateral bargaining this allows us to determine the price level endogenously and leads to additional insights concerning the role of money for example we find that monetary equilibria are generally inefficient in the sense that output and prices differ from the solution to a social planner s problem although the difference can become small as the discount rate or search friction vanishes we also find that there exist nonstationary inflationary equilibria

money and prices a model of search and bargaining abstract this paper makes commodities divisible and incorporates bargaining into the search theoretic model of money to determine the purchasing power of money or price it is shown that two monetary equilibria always coexist where fiat money is universally accepted the two equilibria differ in price output welfare and the velocity of money sunspot monetary equilibria exist in which money is universally accepted in all states of the economy multiplicity has novel implications on the effectiveness of currency substitution and exchange market intervention journal of economic literature classification numbers c78 e40

us brazil cotton dispute and the world cotton market us policies for its cotton producers depress world cotton prices adversely affecting exporters such as brazil which filed a complaint to the wto despite wto rulings in brazil s favour meting out the right to enact retaliatory countermeasures the united states continues to subsidise its cotton farmers after prolonged negotiations brazil and the united states reached an agreement which allowed the united states to pay brazil to refrain from enforcing the countermeasures to capture the adverse effects of us policies theoretical analyses are conducted the theoretical model is extended by constructing an empirical model of the world cotton market the adverse effects of us policies on brazil are estimated and compared to the compensation the united states pays brazil

the welfare costs of expected and unexpected inflation the monetary search model by lagos and wright 2005 is extended with imperfect information about nominal shocks as in lucas 1972 an analytical solution exists with logarithmic preferences in general individuals hold precautionary balances calibrated to united states postwar data the welfare cost of the monetary cycle is calculated to be small below 0 0003 of gdp compared to the welfare cost of the inflation tax around 0 25 of gdp the main reason for the minute welfare cost of the monetary cycle is its low amplitude in 1947 2007 but monetary crashes such as those experienced during the great depression can generate important welfare costs

coexistence of money and interest bearing securities abstract a random matching model with money is used to study the nominal yield on small denomination bearer safe discount securities issued by the government there is always one steady state with matured securities circulating at par and for some parameters another with them circulating at a discount in the former a necessary and sufficient condition for a positive nominal yield on not yet matured securities is exogenous discriminatory treatment of them by the government in the latter the post maturity discount on securities induces a deeper pre maturity discount even without such discriminatory treatment

price dispersion information and learning abstract we consider an economy where trade is decentralized and agents have incomplete information with respect to the value of money agents learning evolves from private experiences and we explore how the formation of prices interacts with learning we show that multiple equilibria arise and equilibria with price dispersion entail more learning than equilibria with one price price dispersion increases communication about private histories which in turn increases the overall amount of information in the economy we also compare ex ante welfare under price dispersion and one price our results show that despite the existence of some meetings where no trade takes place ex ante welfare under price dispersion may be higher than under one price

a new suggestion for simplifying the theory of money we propose a new search theoretic model of monetary exchange with indivisible assets based on price posting instead of bargaining and incorporating noisy search this yields some familiar results plus a lot more the model admits multiple steady states due to the self referential nature of liquidity it admits cyclic chaotic and stochastic equilibria and compared to bargaining versions the dynamics are more general and have better microfoundations it generates price dispersion with interesting efficiency implications plus sticky prices and rational inattention parametric examples yield closed form solutions based on these results we suggest this should become a benchmark model in monetary economics

efficient propagation of shocks and the optimal return on money abstract we study optimal allocations in an environment in which money is essential due to lack of commitment and anonymity of individuals because the economy features aggregate preference shocks we apply a notion of implementability that allows for allocations with non trivial business cycle dynamics for the propagation of shocks we show that history dependence is predicted by the theory of second best and becomes necessary for optimality when the degree of patience is neither too low nor too high our analysis concludes with a discussion of whether there is a role for the propagation of shocks in alternative economic environments

short run and long run effects of changes in money in a random matching model a random matching model of money is used to deduce the effects of a once for all change in the quantity of money it is shown that the change has short run effects that are predominantly real and long run effects that are in the direction of being predominantly nominal provided that the change is random and people learn its realization only with a lag the change in the quantity of money comes about through a random process of discovery that does not permit anyone to deduce the aggregate amount discovered when the change actually occurs

mobilizing private finance to drive an energy industrial revolution abstract while uptake of renewable energies as a solution to climate change is widely discussed the issue of public vs private financing is not yet adequately explored the debates over the kyoto protocol and its successor culminating in the cop15 climate change conference in copenhagen in december 2009 maintained a strong preference for public over private financing yet it is also clear to most observers that the energy revolution will never happen without the involvement of private finance to drive private investment in this viewpoint we discuss the ways in which private financing could be mobilized to drive the energy industrial revolution that is needed if climate change mitigation is to succeed

adaptive learning and monetary exchange abstract this paper investigates three classic questions in monetary theory how can an intrinsically worthless asset such as fiat money maintain value as a medium of exchange what are the short run and long run effects of a change in the money supply what is the social cost of inflation i answer these questions using a microfounded model of monetary exchange that replaces the rational expectations assumption with an adaptive learning rule first i show that monetary exchange is a robust arrangement in the sense that agents are able to learn the stationary monetary equilibrium while the non monetary equilibrium is unstable under learning second an unanticipated monetary injection has real effects in the short run because learning the value of money takes time in the long run agents successfully learn the value of money hence money is neutral third under a constant money growth policy an increase in the growth rate of money increases output in the short run producing a short run phillips curve a ten percent increase in the money growth rate has a social cost of 0 41 percent of output per year alternatively a ten percent decrease in the money growth rate has a social benefit of 0 37 percent of output per year

nonneutrality of money in dispersion hume revisited for a class of standard and widely used preferences a one shot money injection in a standard matching model can induce a significant and persistent output response by dispersing the distribution of wealth decentralized trade matters for both persistence and significance in the presence of government bonds the injection has a liquidity effect and the inflation rate right following the injection may be below the steady state rate level

learning from private and public observations of othersʼ actions we study how a continuum of agents learn about disseminated information by observing others actions every period each agent observes a public and private noisy signal centered around the aggregate action taken by the population the public signal represents an endogenous aggregate variable such as a price or a quantity the private signal represents the information gathered through private communication and local interactions we identify conditions such that the average learning curve is s shaped learning is slow initially intensifies rapidly and finally converges slowly to the truth we show that increasing public information always slows down learning in the long run and under some conditions reduces welfare lastly optimal diffusion of information requires that agents strive to be different agents need to be rewarded for choosing actions away from the population average

a unified framework for monetary theory and policy analysis search theoretic models of monetary exchange are based on explicit descriptions of the frictions that make money essential however tractable versions of these models typically make strong assumptions that render them ill suited for monetary policy analysis we propose a new framework based on explicit micro foundations within which macro policy can be studied the framework is analytically tractable and easily quantifiable we calibrate the model to standard observations and use it to measure the cost of inflation we find that going from 10 percent to 0 percent inflation is worth between 3 and 5 percent of consumption much higher than previous estimates

the adjustment of prices to monetary shocks when trade is uncertain and sequential trade is both uncertain and sequential money surprises are not neutral because prices at the beginning of the trading process cannot depend on its end in contrast with fixed price models in this paper sellers can change prices during trade in contrast with lucas s article here there is no asymmetry in the information about the money supply the price quoted by individual sellers may adjust slowly to changes in the targeted money supply but the distribution of quoted prices adjusts perfectly to these changes and the real price distribution is independent of the anticipated rate of change in the money supply

liquidity quality production cost and welfare in a search model of money this paper examines a search model of money with divisible commodities of high and low quality while keeping the assumptions of indivisible money and unit inventory constraint with no direct barter and a higher fixed cost of producing high relative to low quality an increase in the money stock encourages the production of high quality output by trading off the larger trading opportunities against the significance of higher fixed cost as long as the fixed cost differential between high and low quality is sufficiently small relative to the utility gain from high quality consumption the quality improvement outweighs the negative effect of higher money stocks on aggregate production and hence implies higher welfare the most important function of money is its role as a medium of exchange wicksell 1906 1967 p 17 defined a general medium of exchange to be an object which is habitually and without hesitation taken by anybody in exchange for any commodity the main challenge facing monetary theory is to construct a model which permits the object s role in exchange to be endogenous 1 kiyotaki and wright 1991 1993 seems to be the first fully coherent model which specifies the environment and equilibrium concept in a way that does not force at the outset the assumption on which objects will play a special role in trade the kiyotaki wright model departs from the physical environment of the standard general equilibrium model through the assumption that trading histories are private information the medium of exchange role of money is obtained as an outcome of nash equilibrium together with some bargaining rule in pairwise random meetings however the standard kiyotaki wright model yields an undesirable welfare implication that an increase in the money stock eventually leads to a decrease in welfare because of a decrease in the number of agents who get to consume in a given period the same welfare property is obtained in the models with divisible commodities such as trejos and wright 1995 and shi 1995 2 this property has been regarded as the outcome of the original kiyotaki wright assumptions of indivisible money and the inventory constraint agents can only carry one object either commodity or money at a time despite simplifying the distribution of money holdings these assumptions impose the restriction that agents are not allowed to produce while they hold money

the distribution of money balances and the nonneutrality of money recent monetary models with explicit microfoundations are made tractable by assuming that agents have access to centralized markets after one round of decentralized trade given quasi linear preferences this makes the distribution of money degenerate which keeps the models simple but precludes the discussion of distributional effects of monetary policy we generalize these models by assuming two rounds of trade before agents can readjust their money holdings to study a range of new distributional effects analytically we show that unexpected symmetric lump sum money injections may increase short run output and welfare whereas asymmetric injections may increase long run output and welfare