robust stochastic discount factors when the market is incomplete a new non redundant derivative security cannot be priced by no arbitrage arguments alone moreover there will be a multiplicity of stochastic discount factors and each of them may give a different price for the new derivative security this paper develops an approach to the selection of a stochastic discount factor for pricing a new derivative security the approach is based on the idea that the price of a derivative security should not vary too much when the payoff of the primitive security is slightly perturbed i e the price of the derivative should be robust to model misspecification the paper develops two metrics of robustness the first is based on robustness in expectation the second is based on robustness in probability and draws on tools from the theory of large deviations we show that in a stochastic volatility model the two metrics yield analytically tractable bounds for the derivative price as the underlying stochastic volatility model is perturbed the bounds can be readily used for numerical examination of the sensitivity of the price of the derivative to model misspecification

dusenberry s ratcheting of consumption optimal dynamic consumption and investment given intolerance for any decline in standard of living duesenberry s ratcheting consumption demand is derived as a feature of the optimal dynamic consumption and investment policy given extreme habit formation that prevents consumption from falling over time preferences are in effect non time separable extended real valued von neumann morgenstern preferences consumption increases each time wealth reaches a new maximum risky investment is proportional to the excess of wealth over the perpetuity value of current consumption extensions constrain the net rate of decrease in consumption with a constant other than zero add more consumption goods and constrain on the maximal holding of the risky asset as a proportion of wealth these strategies may be useful for the management of university endowments participatory investment accounts and risky arbitrage funds

surplus debt regressions abstract single equation estimates of fiscal reaction functions which relate primary surpluses to past debt gdp ratios and control variables are subject to potentially serious simultaneity bias that can produce misleading inferences about fiscal behavior biases arise from failure to model the general equilibrium relationships between government debt and surpluses relationships that bring in the forward looking nature of nominal debt valuation and the role of monetary policy in that valuation

dissecting fiscal multipliers under the fiscal theory of the price level abstract we derive analytical expressions for fiscal multipliers on output and inflation under the fiscal theory of the price level in the associated fiscal regime taxation multipliers turn positive while the government spending multiplier has the same functional form as its counterpart in the monetary regime augmented by a nominal wealth effect as a result fiscal multipliers tend to be larger in the fiscal regime with the degree of price stickiness being a key determinant of their exact sizes in particular multipliers go to infinity as prices become fully fixed and collapse to their equivalents in the monetary regime as prices become fully flexible standard calibrations suggest that the fiscal regime hosts a government spending multiplier on output that lies between 1 and 3 we also analyze the effectiveness of money financed fiscal stimulus in the fiscal regime money financed stimulus is equivalent to a particular form of debt financed stimulus the effectiveness of money financed stimulus in raising output relative to inflation decreases as monetary policy becomes more responsive to inflation

on arbitrage free pricing of interest rate contingent claims unlike most interest rate claim models the ho lee model utilizes full information on the current term structure unfortunately the model has a major deficiency in that negative interest rates can occur this article modifies the model such that interest rates are well behaved

a dynamic programming approach for pricing options embedded in bonds abstract we propose a dynamic programming dp approach for pricing options embedded in bonds the focus being on call and put options with advance notice an efficient procedure is developed for the cases where the interest rate process follows the vasicek cox ingersoll ross cir or generalized vasicek models our dp methodology uses the exact joint distribution of the interest rate and integrated interest rate at a future date conditional on the current value of the interest rate we provide numerical illustrations for the vasicek and cir models comparing our dp method with finite difference methods our procedure compares quite favorably in terms of both efficiency and accuracy an important advantage of the our dp approach is that it can be applied to more general models calibrated to capture the term structure of interest rates e g the generalized vasicek model

evolving monetary fiscal policy mix in the united states a micro founded model that allows for changes in the monetary fiscal policy mix and in the volatility of structural shocks is fit to us post wwii data agents are aware of the possibility of regime changes and their beliefs have an impact on the law of motion of the macroeconomy the results show that the 60s and the 70s were characterized by a prolonged period of active fiscal policy and passive monetary policy the appointment of volcker marked a change in the conduct of monetary policy but it took almost ten years for the fiscal authority to start accommodating this regime change

consumption and saving with habit formation and durability abstract this paper develops a model of precautionary saving with habit formation and durability durability offsets the effects of habit formation on both consumption growth and the precautionary premium empirical tests of habit formation and durability on consumption growth might exploit their parallel effects on the precautionary premium

valuing managerial flexibility an application of real option theory to mining investments abstract the value of managerial flexibility is assessed using data on prices costs grades reserves ore extraction and metal output for a panel of canadian copper mines a real option model is estimated and solved for project and option values most empirical researchers i consider the initial investment decision but neglect flexible operation thereafter ii assume that price is stochastic but ignore cost and reserve uncertainty and iii model price as a nonstationary stochastic process the evolution of three state variables price cost and reserves is assessed here differences in assumptions compared to others are found to lead to large differences in estimated project and option values

measuring quality change in quota constrained import markets the case of u s footwear abstract theoretical models predict that quantitative import restrictions such as orderly marketing agreements omas lead to substitution into higher quality products within the quotaconstrained import category the country specific nature of omas results in further substitution among supplying countries using index number techniques this paper measures the impact of product and country substitution on the price of u s footwear imports in the period surrounding the 1977 1981 footwear oma with korea and taiwan upgrading of the import bundle was observed in most quota categories throughout the oma period and accounted for 12 percent of the observed rise in the average price of footwear imports

testing for indeterminacy an application to u s monetary policy reply this paper considers a prototypical new keynesian model in which the equilibrium is undetermined if monetary policy is passive the likelihood based estimation of dynamic equilibrium models is extended to allow for indeterminacies and sunspot fluctuations we construct posterior weights for the determinacy and indeterminacy region of the parameter space and estimates for the propagation of fundamental and sunspot shocks according to the estimated model u s monetary policy post 1982 is consistent with determinacy whereas the pre volcker policy is not we find that before 1979 indeterminacy substantially altered the propagation of shocks

monetary fiscal policy interaction and fiscal inflation a tale of three countries abstract we study the impact of the interaction between fiscal and monetary policy on the low frequency relationship between the fiscal stance and inflation using cross country data from 1965 to 1999 in a first step we contrast the monetary fiscal narrative for germany the u s and italy with evidence obtained from simple regression models and a time varying var we find that the low frequency relationship between the fiscal stance and inflation is low during periods of an independent central bank and responsible fiscal policy and more pronounced in times of non responsible fiscal policy and accommodative monetary authorities in a second step we use an estimated dsge model to interpret the low frequency measure structurally and to illustrate the mechanisms through which fiscal actions affect inflation in the long run the findings from the dsge model suggest that switches in the monetary fiscal policy interaction and accompanying variations in the propagation of structural shocks can well account for changes in the low frequency relationship between the fiscal stance and inflation

an isomorphism between asset pricing models with and without linear habit formation we show an isomorphism between optimal portfolio selection or competitive equilibrium models with utilities incorporating linear habit formation and corresponding models without habit formation the isomorphism can be used to mechanically transform known solutions not involving habit formation to corresponding solutions with habit formation for example the constantinides 1990 and ingersoll 1992 solutions are mechanically obtained from the familiar merton solutions for the additive utility case without recourse to a bellman equation or first order conditions more generally recent solutions to portfolio selection problems with recursive utility and a stochastic investment opportunity set are readily transformed to novel solutions of corresponding problems with utility that combines recursivity with habit formation the methodology also applies in the context of hindy huang kreps 1992 preferences where our isomorphism shows that the solution obtained by hindy and huang 1993 can be mechanically transformed to dybvig s 1995 solution to the optimal consumption investment problem with consumption ratcheting this article presents a general method for solving asset pricing or portfolio selection models involving linear habit formation of the type studied by sundaresan 1989 constantinides 1990 detemple and zapatero 1991 ingersoll 1992 chapman 1998 and others the basic idea we pursue is that linear habit formation can be thought of as a redefinition of what constitutes consumption to include not only the current consumption rate but also a fictitious possibly negative consumption rate derived from past actual consumption by pricing out this fictitious consumption rate correctly the economy with linear habit formation can be mechanically transformed to an equivalent economy without habit formation this analysis simplifies and unifies existing results but also generates novel solutions for example together with the results of schroder and skiadas 1997 1999 our method produces optimal lifetime consumption and portfolio policies with preferences that combine recursive utility with habit formation under a stochastic

asset integration and attitudes to risk theory and evidence measures of risk attitudes derived from experiments are often questioned because they are based on small stakes bets and do not account for the extent to which the decision maker integrates the prizes of the experimental tasks with personal wealth we exploit the existence of detailed information on individual wealth of experimental subjects in denmark and directly estimate risk attitudes and the degree of asset integration consistent with observed behavior the behavior of the adult danes in our experiments is consistent with partial asset integration they behave as if some small fraction of personal wealth is combined with experimental prizes in a utility function and that this combination entails less than perfect substitution our subjects do not perfectly asset integrate the implied risk attitudes from estimating these specifications imply risk premia and certainty equivalents that are a priori plausible under expected utility theory or rank dependent utility models these are reassuring and constructive solutions to payoff calibration paradoxes in addition the rigorous structural modeling of partial asset integration points to a rich array of neglected questions in risk management and policy evaluation in important field settings

u s monetary regimes and optimal monetary policy in the euro area monetary policy in the united states has been documented to have switched from reacting weakly to inflation fluctuations during the 1970s to fighting inflation aggressively from the early 1980s onward in this paper i analyze the impact of the u s monetary policy regime switches on the eurozone i construct a new keynesian two country model where foreign u s monetary policy switches regimes over time i estimate the model for the u s and the euro area using quarterly data and find that the united states has switched between those two regimes in line with existing evidence i show that foreign regime switches affect home eurozone inflation and output volatility and their responses to shocks substantially as long as the home central bank commits to a time invariant interest rate rule reacting to domestic conditions only optimal policy in the home country instead requires that the home central bank reacts strongly to domestic producer price inflation and to international variables such as imported goods relative prices in fact i show that currency misalignments and relative prices play a crucial role in the transmission of foreign monetary policy regime switches internationally interestingly i show that only marginal gains arise for the euro area when the european central bank ecb adjusts its policy according to the monetary regime in the united states thus a simple time invariant monetary policy rule with a strong reaction to producer price index ppi inflation and relative prices is enough to counteract the effects of monetary policy switches in the united states

continuous time methods in finance a review and an assessment i survey and assess the development of continuous time methods in finance during the last 30 years the subperiod 1969 to 1980 saw a dizzying pace of development with seminal ideas in derivatives securities pricing term structure theory asset pricing and optimal consumption and portfolio choices during the period 1981 to 1999 the theory has been extended and modified to better explain empirical regularities in various subfields of finance this latter subperiod has seen significant progress in econometric theory computational and estimation methods to test and implement continuous time models capital market frictions and bargaining issues are being increasingly incorporated in continuous time theory the roots of modern continuous time methods in finance can be traced back to the seminal contributions of merton 1969 1971 1973b in the late 1960s and early 1970s merton 1969 pioneered the use of continuous time modeling in financial economics by formulating the intertemporal consumption and portfolio choice problem of an investor in a stochastic dynamic programming setting merton 1973b also showed how such a framework can be used to develop equilibrium asset pricing implications thereby significantly extending the asset pricing theory to richer dynamic settings and expanding the scope of applications of continuous time methods to study problems in financial economics 1 within a span of about 30 years from the publication of merton s inf luential papers continuous time methods have become an integral part of financial economics indeed in certain core areas in finance such as e g asset pricing derivatives valuation term structure theory and portfolio selection continuoustime methods have proved to be the most attractive way to conduct research and gain economic intuition the continuous time approach in these areas has produced models with a rich variety of testable implications the econometric theory for testing continuous time models has made rapid strides in the last decade and has thus kept pace with the impressive progress on the theoretical front one hopes that the actual empirical investigations and estimation using the new procedures will follow suit soon

the effect of temporal risk aversion on liquidity preference abstract in most instances investors are not indifferent to risk their attitudes toward it influence their decisions temporal risk aversion the dynamic analogue of the usual concept of risk aversion has a marked effect on investors decisions but is usually ignored in the literature this paper investigates the liquidity preference of temporally risk averse investors the analysis shows that all other things being equal temporal risk aversion reduces the liquidity premium investors must receive to hold an asset that is not perfectly reversible thus the optimal investment policy is closer to what one would expect had a frictionless exchange market existed for the irreversible asset as far as an individual s investment behavior is concerned temporal risk aversion counters the effects of an asset s irreversibility and tends to compensate for the absence of frictionless exchange

an intertemporal general equilibrium model of asset prices this paper develops a continuous time general equilibrium model of a simple but complete economy and uses it to examine the behavior of asset prices in this model asset prices and their stochastic properties are determined endogenously one principal result is a partial differential equation which asset prices must satisfy the solution of this equation gives the equilibrium price of any asset in terms of the underlying real variables in the economy in this paper we develop a general equilibrium asset pricing model for use in applied research an important feature of the model is its integration of real and financial markets among other things the model endogenously determines the stochastic process followed by the equilibrium price of any financial asset and shows how this process depends on the underlying real variables the model is fully consistent with rational expectations and maximizing behavior on the part of all agents our framework is general enough to include many of the fundamental forces affecting asset markets yet it is tractable enough to be specialized easily to produce specific testable results furthermore the model can be extended in a number of straightforward ways consequently it is well suited to a wide variety of applications for example in a companion paper cox ingersoll and ross 7 we use the model to develop a theory of the term structure of interest rates many studies have been concerned with various aspects of asset pricing under uncertainty the most relevant to our work are the important papers on intertemporal asset pricing by merton 19 and lucas 16 working in a continuous time framework merton derives a relationship among the equilibrium expected rates of return on assets he shows that when investment opportunities are changing randomly over time this relationship will include effects which have no analogue in a static one period model lucas considers an economy with homogeneous individuals and a single consumption good which is produced by a number of processes the random output of these processes is exogenously determined and perishable assets are defined as claims to all or a part of the output of a process and the equilibrium determines the asset prices our theory draws on some elements of both of these papers like merton we formulate our model in continuous time and make full use of the analytical tractability that this affords the economic structure of our model is somewhat similar to that of lucas however we include both endogenous production and

a continuous time equilibrium model of forward prices and futures prices in a multigood economy abstract this paper is a theoretical investigation of equilibrium forward and futures prices we construct a rational expectations model in continuous time of a multigood identical consumer economy with constant stochastic returns to scale production using this model we find three main results first we find formulas for equilibrium forward futures discount bond commodity bond and commodity option prices second we show that a futures price is actually a forward price for the delivery of a random number of units of a good the random number is the return earned from continuous reinvestment in instantaneously riskless bonds until maturity of the futures contract third we find and interpret conditions under which normal backwardation or contango is found in forward or futures prices these conditions reflect the usefulness of forward and futures contracts as consumption hedges

an empirical model of mark ups in a quality differentiated export market abstract this paper develops an empirical model to allow for imperfect competition in the market for traded goods a simultaneous equation model incorporating the demand for and supply of taiwanese footwear exports to the united states is specified and estimated the model allows the identification of two separate sources of mark ups in export prices the first comes from the u s imposed quantitative restriction on these exports the second comes from imperfect competition in the international market for these exports the results suggest competitive behavior by taiwanese footwear exporters the quantitative restriction resulted in a 16 9 percent mark up of prices over marginal cost

e stability vis a vis determinacy in regime switching models abstract this paper examines e stability determinacy and indeterminacy in a general class of regime switching models with lagged endogenous variables using determinacy conditions from cho 2016 2020 our first result extends mccallum 2007 to models with time varying parameters the unique mean square stable equilibrium is e stable if agents have current information and one period ahead decision rules further we address the existence of e stable non fundamental equilibria and find that iteratively e stable equilibria of indeterminate switching models can exist finally we show that indeterminate new keynesian models with persistent recurring interest rate peg regimes admit iteratively e stable equilibria in special cases the iterative e stability condition coincides with the long run taylor principle

controlling inflation with timid monetary fiscal regime changes can monetary policy control inflation when both monetary and fiscal policies change over time when monetary policy is active a long run fiscal principle entails flexibility in fiscal policy that preserves determinacy even when deviating from passive fiscal substantially for brief periods or timidly for prolonged periods in order to guarantee a unique equilibrium monetary and fiscal policies must coordinate not only within but also across regimes and not simply on being active or passive but also on their extent the amplitude of deviations from the active monetary passive fiscal benchmark determines whether a regime is ricardian timid deviations do not imply wealth effects

stepping on a rake the role of fiscal policy in the inflation of the 1970s abstract the inflation of the 1970s in the us is often discussed as if the only type of policy action that could have prevented the inflation were monetary policy actions and the only type of policy errors that might have induced the inflation were monetary policy errors yet fiscal policy underwent dramatic shifts in the 1970s and economic theory makes clear that in an environment of uncertainty about future fiscal policy monetary policy instruments may lose potency or have perverse effects this paper documents the vagaries of fiscal policy in this period and argues that people at the time must have been uncertain about fiscal policy s future course it also lays out a theoretical framework for understanding the effects of fiscal uncertainties on monetary policy and shows that fiscal variables have predictive value in dynamic models even if traditional monetary policy indicators are included in the system

time horizon and the discount rate abstract we consider an economy a la lucas 1978 econometrica46 1429 1446 with a risk averse representative agent the exogenous growth rate of the economy follows a random walk we characterize the set of utility functions for which it is efficient to discount more distant cash flows at a lower rate the benchmark result is that when the growth rate is almost surely nonnegative the yield curve is decreasing if and only if relative risk aversion is decreasing with wealth relaxing the assumption on the absence of recession requires more restrictions on preferences such as increasing relative prudence journal of economic literature classification numbers d81 d91 q25 q28

the effect of temporal risk aversion on optimal consumption the equity premium and the equilibrium interest rate this paper demonstrates that temporal risk aversion makes smoothing consumption over time less attractive while the usual risk aversion makes it more attractive as temporal risk aversion increases the equilibrium interest rate decreases and the equity premium increases this paper also shows a striking and novel result that an increase in time impatience can lead to either a decrease or an increase in the interest rate depending on the nature of the nonseparability

frequentist evaluation of small dsge models this article proposes a new evaluation approach for the class of small scale hybrid new keynesian dynamic stochastic general equilibrium nk dsge models typically used in monetary policy and business cycle analysis the empirical assessment of the nk dsge model is based on a conditional sequence of likelihood based tests conducted in a vector autoregressive var system in which both the low and high frequency implications of the model are addressed in a coherent framework if the low frequency behavior of the original time series of the model can be approximated by nonstationary processes stationarity must be imposed by removing the stochastic trends this gives rise to a set of recoverable unit roots cointegration restrictions in addition to the short run cross equation restrictions the procedure is based on the sequence lr1 lr2 lr3 where lr1 is the cointegration rank test lr2 is the cointegration matrix test and lr3 is the cross equation restrictions test lr2 is computed conditional on lr

the relative inefficiency of quotas the cheese case the nonequivalence of tariffs and quotas under a wide variety of circumstances is well established in economic theory this study considers heterogeneity as a source of nonequivalence and demonstrates its practical importance where restriction is inevitable the bias of economists in favor of price instruments is not thoroughly grounded this study should help provide a foundation the point of departure from the equivalence model is differentiation of products

nominal contracts in a bimetallic standard as its central feature a bimetallic standard grants nominal debtors an option to deliver either of two metals with results from the option pricing literature construction of a formula to evaluate the bimetallic option in debt instruments is straightforward with this formula one can compute the option value in a wide range of nineteenth century u s treasury securities posession of the option values permits an adjustment of the yields on u s securities to make them comparable to yields on nonmetallic european securities evaluating the option allows the estimation of transfers from debtors to creditors copyright 1986 by american economic association

time preference and capital asset pricing models abstract results of the theory of individual optimal consumption investment choice under uncertainty are extended to a class of intertemporally dependent preferences for consumption streams these results are then used to show that with intertemporally dependent preferences which are more realistic than the separable time additive preference structure merton s 1973 multi beta intertemporal capital asset pricing model is still valid but it can no longer be collapsed to breeden s 1979 single consumption beta model

trade policy and its impact on quality of imports this paper examines the role of trade policies in influencing a foreign monopolist s decision on price quantity and in particular the quality of its product we show that a specific tariff leads to higher quality whereas an ad valorem tariff usually does the opposite quotas and specific tariffs are shown to be equivalent and both dominate an ad valorem tariff in terms of welfare we also show that subjecting imports to minimum quality requirements hampers national welfare finally we present a comprehensive ranking of all the policy instruments considered in this paper

indexing the income tax code monetary fiscal interaction and the great moderation abstract this paper considers the consequences of automatically indexing the us federal income tax code to inflation indexation implemented during the 1981 federal tax overhaul and active monetary policy constitute necessary conditions for a unique rational expectations equilibrium in standard new keynesian models with a generalized progressive labor income tax additionally fixing the monetary regime shows that indexation reduces overall volatility in the model as well as the contribution of supply side disturbances together these results support a fiscal extension to the good policy hypothesis of the great moderation and encourage further indexation of the united states tax code

fiscal consolidations and heterogeneous expectations abstract we analyze fiscal consolidations using a new keynesian model where agents have heterogeneous expectations and are uncertain about the composition of consolidations we look at spending based and tax based consolidations and analyze their effects separately we find that the effects of consolidations and the output multipliers are sensitive to heterogeneity in expectations before and after implementation of a specific fiscal plan depending on the beliefs about the type of consolidation prior to implementation we show that heterogeneity in expectations may lead to optimism in the economy improving thus the performance of a specific fiscal plan or can work towards the opposite direction leading to pessimism amplifying the contractionary effects of the consolidation in general we find that spending based consolidations last longer and lead to deeper recessions when agents are boundedly rational compared to the rational expectations benchmark while the opposite holds for tax based consolidations

uncertainty and fiscal cliffs motivated by the us fiscal cliin 2012 this paper considers the short and longer term impact of uncertainty generated by scal policy empirical evidence shows in creases in economic policy uncertainty lower investment and employment investment that is longer lived and subject to a longer planning horizon responds to policy uncer tainty with a lag while capital that depreciates more quickly and can be installed with few costs falls immediately a dsge model incorporating uncertainty over future tax regimes produces responses to scal uncertainty that match key features of the data the model features uncertainty over the average tax rate and rational expectations about the resolution of uncertainty with speci c outcomes and timing uncertainty injects noise into the economy and lowers the level of economic activity

single factor heath jarrow morton term structure models based on markov spot interest rate dynamics this paper considers the class of heath jarrow morton term structure models where the spot interest rate is markov and the term structure at time t is a function of time maturity and the spot interest rate at time t a representation for this class of models is derived and i show that the functional forms of the forward rate volatility structure and the initial forward rate curve cannot be arbitrarily chosen i provide necessary and sufficient conditions indicating which combinations of these functional forms are allowable i also derive a partial differential equation representation of the term structure dynamics that does not require explicit modeling of both the market price of risk and the drift term for the spot interest rate process using the analysis presented in this paper a class of intertemporal term structure models is derived

optimal consumption and portfolio rules with intertemporally dependent utility of consumption abstract in the usual consumption portfolio problem lifetime utility is assumed to be time additive this assumption has been criticized for failing to capture important intertemporal dependencies in utility such as intertemporal risk aversion and habit formation this paper studies the consumption portfolio problem for a class of intertemporally dependent utility functions

tariffs versus quotas with endogenous quality this paper analyzes the effects and desirability of tariffs quotas and quality controls when the quality of the imported good is endogenous and the foreign producer is a monopolist a crucial determinant of the direction of these effects is shown to be the valuation of increments in quality by the marginal consumer relative to that of all consumers on average a way of comparing infinitesimal equivalent policies is developed and used to compare import equivalent policies

changing macroeconomic dynamics at the zero lower bound this article develops a change point var model that isolates four major macroeconomic regimes in the us since the 1960s the model identifies shocks to demand supply monetary policy and spread yield using restrictions from a general equilibrium model the analysis discloses important changes to the statistical properties of key macroeconomic variables and their responses to the identified shocks during the crisis period spread shocks became more important for movements in unemployment and inflation a counterfactual exercise evaluates the importance of lower bond yield spread during the crises and suggests that the fed s large scale asset purchases helped lower the unemployment rate by about 0 6 percentage points while boosting inflation by about 1 percentage point

reference point dependence and specification bias abstract issues of specification bias arise in deterministic as well as in econometric models this paper shows that such biases depend on the reference point used to evaluate them using numerical general equilibrium models in which the incorporation of quality upgrading in the competitive case increases or reduces the welfare costs of trade barriers depending upon whether a trade distorted equilibrium or free trade is used as the reference point

long term debt and optimal policy in the fiscal theory of the price level the fiscal theory says that the price level is determined by the ratio of nominal debt to the present value of real primary surpluses i analyze long term debt and optimal policy in the fiscal theory i find that the maturity structure of the debt matters for example it determines whether news of future deficits implies current inflation or future inflation when long term debt is present the government can trade current inflation for future inflation by debt operations this tradeoff is not present if the government rolls over short term debt the maturity structure of outstanding debt acts as a budget constraint determining which periods price levels the government can affect by debt variation alone in addition debt policythe expected pattern of future state contingent debt sales repurchases and redemptionsmatters crucially for the effects of a debt operation i solve for optimal debt policies to minimize the variance of inflation i find cases in which long term debt helps to stabilize inflation i also find that the optimal policy produces time series that are similar to u s surplus and debt time series to understand the data i must assume that debt policy offsets the inflationary impact of cyclical surplus shocks rather than causing price level disturbances by policy induced shocks shifting the objective from price level variance to inflation variance the optimal policy produces much less volatile inflation at the cost of a unit root in the price level this is consistent with the stabilization of u s inflation after the gold standard was abandoned

were there regime switches in u s monetary policy working paper 2004 14 june 2004 abstract a multivariate model identifying monetary policy and allowing for simultaneity and regime switching in coefficients and variances is confronted with u s data since 1959 the best fit is with a model that allows time variation in structural disturbance variances only among models that also allow for changes in equation coefficients the best fit is for a model that allows coefficients to change only in the monetary policy rule that model allows switching among three main regimes and one rarely and briefly occurring regime the three main regimes correspond roughly to periods when most observers believe that monetary policy actually differed and the differences in policy behavior are substantively interesting though statistically ill determined the estimates imply monetary targeting was central in the early 80s but was also important sporadically in the 70s the changes in regime were essential neither to the rise in inflation in the 70s nor to its decline in the 80s jel classification e52 e47 c53 key words counterfactuals lucas critique policy rule monetary targeting simultaneity volatility model comparison i the debate over monetary policy change in an influential paper clarida gali and gertler 2000 cgg presented evidence that us monetary policy changed between the 1970 s and the 1980 s indeed that in the 70 s it was drastically worse they found that the policy rule apparently followed in the 70 s was one that when embedded in most stochastic general equilibrium models would imply non uniqueness of the equilibrium and hence vulnerability of the economy to sunspot fluctuations of arbitrarily large size their estimated policy rule for the later period on the other hand eliminated this indeterminacy these results are a possible explanation of the volatile and rising inflation of the 70 s and of its subsequent decline the cgg analysis has two important weaknesses one is that it fails to account for stochastic volatility us macroeconomic variables and particularly the federal funds rate have gone through periods of tranquility and of agitation with forecast error variances varying greatly from period to period ignoring such variation does not lead to inconsistent estimates of model parameters when the forecasting equations themselves are constant but it strongly biases toward a finding of changed parameters tests of the stability of the forecasting equations the other weakness is that the cgg analysis rests on powerful and implausible identifying assumptions they require that we accept that the response of the monetary authority to expected future inflation and output does not depend on the recent history of inflation money growth or output it is hard to understand why this should be so especially in the 70 s when monetarism was a prominent theme in policy debates congress was requiring reports from the fed of projected time paths of monetary aggregates and financial markets were reacting sensitively to weekly money supply numbers the requirement for existence and uniqueness of equilibrium in dynamic models is that the monetary policy rule show a more than unit response of interest rates to the sum of the logs of all nominal variables that appear on the right hand side of the reaction function if we force a particular measure of expected future inflation to proxy for all the nominal variables that actually appear independently in the reaction function we are bound to get distorted conclusions on the one hand because expected future inflation will be a noisy measure of the full set of nominal influences on policy we might get downward bias in our estimates from the usual errorsin variables effect on the other hand to the extent that expected future inflation like most expected future values shows less variation than current nominal variables we could find a mistaken scaling up of coefficients

moment based estimation of stochastic volatility abstract this paper makes use of the distributional information contained in high frequency data to test for the specification of the functional form of the volatility process within the class of stochastic volatility models it s calculus is implemented in order to obtain the first and second conditional moment of the driving stochastic differential equation for the volatility process these analytical expressions are augmented by their lag and lag squared and are used to form the corresponding gmm estimator the base case stochastic volatility model is extended to allow for the leverage effect and jumps in returns empirical estimation confirms the presence of fast mean reversion in volatility and jumps in returns for the 5 min s p 500 stock market index further estimation results also seem to indicate the presence of jumps in the volatility process that are correlated to the jumps in returns

solving endogenous regime switching models abstract this paper solves rational expectations models in which structural parameters switch across multiple regimes according to state dependent endogenous transition probabilities assuming small shocks and smooth transition probabilities we apply a perturbation approach we first provide for conditions under which a unique bounded equilibrium exists we then compute first and second order approximations in a new keynesian model with monetary policy switching we document new effects of monetary policy switching when transition probabilities depend on inflation

comparative dynamics of an equilibrium intertemporal asset pricing model this paper uses recursive competitive theory to develop a general equilibrium asset pricing model in this framework all prices and rates of return are endogenously determined thus enabling us to analyze the effects of changes in preferences technological uncertainty and expectations on the structure of security prices in particular we focus on how the market risk premium varies with changes in the underlying economic environment an issue which other asset pricing models have chosen not to address

hedging derivative securities and incomplete markets an e arbitrage approach given a european derivative security with an arbitrary payoff function and a corresponding set of underlying securities on which the derivative security is based we solve the optimal replication problem find a self financing dynamic portfolio strategy involving only the underlying securities that most closely approximates the payoff function at maturity by applying stochastic dynamic programming to the minimization of a mean squared error loss function under markov state dynamics we derive recursive expressions for the optimal replication strategy that are readily implemented in practice the approximation error or e of the optimal replication strategy is also given recursively and may be used to quantify the degree of market incompleteness to investigate the practical significance of these e arbitrage strategies we consider several numerical examples including path dependent options and options on assets with stochastic volatility and jumps