on jumps and arch effects in natural resource prices an application to pacific northwest stumpage prices continuous time models of natural resource prices usually preclude the possibility of large changes jumps resulting from unexpected events to test for the presence of jumps and or arch effects we combine bounds and the monte carlo test technique to obtain finite sample level exact p values we apply this methodology to stumpage prices from the pacific northwest and find evidence of jumps and arch effects to assess the impact of neglecting jumps on the decision to harvest old growth timber we develop an autonomous infinite horizon stopping model for which we provide a new method of resolution our numerical results show the importance of modeling jumps explicitly copyright 2002 oxford university press

monetary accommodation exchange rate regimes and inflation persistence stable url http links jstor org sici sici 0013 0133 28199205 29102 3a412 3c461 3amaerra 3e2 0 co 3b2 lthe economic journal is currently published by royal economic society your use of the jstor archive indicates your acceptance of jstor s terms and conditions of use available athttp www jstor org about terms html jstor s terms and conditions of use provides in part that unless you have obtainedprior permission you may not download an entire issue of a journal or multiple copies of articles and you may use content inthe jstor archive only for your personal non commercial use please contact the publisher regarding any further use of this work publisher contact information may be obtained athttp www jstor org journals res html each copy of any part of a jstor transmission must contain the same copyright notice that appears on the screen or printedpage of such transmission the jstor archive is a trusted digital repository providing for long term preservation and access to leading academicjournals and scholarly literature from around the world the archive is supported by libraries scholarly societies publishers and foundations it is an initiative of jstor a not for profit organization with a mission to help the scholarly community takeadvantage of advances in technology for more information regarding jstor please contact support jstor org http www jstor orgwed feb 13 07 34 49 2008

the tree cutting problem in a stochastic environment the case of age dependent growth abstract harvest policies are derived for growing biological assets e g forests livestock subject to stochastic age dependent growth and price uncertainty the task posed is analyzed as a continuous time optimal stopping problem for diffusion processes both single and ongoing rotation problems are considered qualitative comparative static and numerical results are provided

the great appreciation the great depreciation and the purchasing power parity hypothesis abstract although there has been much recent work on purchasing power parity ppp neither univariate nor panel methods have produced strong rejections of unit roots in us dollar real exchange rates for industrialized countries during the post 1973 period we investigate the hypothesis that these non rejections can be explained by one episode the large appreciation and depreciation of the dollar in the 1980s by developing unit root tests which account for this event and maintain long run ppp using panel methods we can strongly reject the unit root null for those countries that adhere to the typical pattern of the dollar s rise and fall

risk aversion and optimal forest replanting a stochastic efficiency study abstract a new stochastic efficiency analysis approach called stochastic efficiency with respect to a function serf is applied to analyse optimal tree replanting on an area of recently harvested forest land serf partitions a set of risky alternative tree replanting strategies in terms of certainty equivalents ces for a specified range of attitudes to risk both the entailed risk and the forest owner s risk aversion are taken into account the forest owner s degree of risk aversion affects both the optimal tree replacement strategy and the reinvestment decision the degree of risk aversion also needs to be taken into account when designing policy measures to affect forest investment

can appreciation be expansionary evidence from the euro area summarywe identify exogenous effects of shifts in effective exchange rates for euro area ea countries between 1999 and 2016 the identification strategy is based on an external instrument built on the assumption that movements in the euro nominal effective exchange rate are largely exogenous for individual ea countries once we control for ea aggregates we find that a real appreciation creates a trade off between expenditure switching contractionary and terms of trade expansionary effects with the latter prevailing in most countries we also find some heterogeneity in the way movements in the euro exchange rate are transmitted within the ea in particular between core and peripheral countries although differences are mostly not statistically significant

the role of spatial scale in the timing of uncertain environmental policy the spatial scale of an environmental problem is dictated by boundaries physical boundaries limit the extent of impacts while the scale of decision making creates perceived boundaries beyond which impacts are ignored by decision makers while it is well understood that uncertainty and irreversibility will alter policy decisions aimed at alleviating environmental impacts the effect of spatial scales both physical and perceived is less understood when spatial scale is included in a real options model of environmental policy adoption results indicate that the importance and influence of spatial considerations depends on the level of uncertainty stringency of the proposed policy and flexibility of the policy decision recognizing spatial scale may force policy adoption to take place within a window of current damage when spatial scale is small or uncertainty high this window for policy adoption can close precluding policy adoption entirely this undermines well known results demonstrating that changes in uncertainty will only alter the timing of policy adoption in other instances the policy adoption window remains open but the option value increases faster than the benefits of the policy creating a scenario where it is always preferable to delay here the inclusion of an option value can prevent adoption of policies that would be adopted according to traditional cost benefit analysis in general policy decisions will be most affected by spatial considerations when the spatial scale is small damage is spreading fast and the uncertainty in damage spread is high

carbon subsidies taxes and optimal forest management we consider the effect of carbon credit payment schemes on forest owners land use and harvest decisions we study two possible credit allocation regimes one where credits are allocated according to the actual amount of carbon sequestered by the trees on a piece of land and another where credits are allocated according to the long run potential to sequester carbon on the land using a real options model with uncertain future timber prices we examine the effect on the timing of harvests and the replanting abandonment decision we show that both schemes discourage deforestation compensating growers for actual carbon sequestration leads to longer rotation periods between harvests while basing compensation only on the long run potential level of sequestration induces shorter rotation periods the former scheme leads to greater benefits of carbon sequestration at lower cost than the latter scheme although inducing moderate levels of sequestration is expensive under both schemes the cost falls dramatically when the level of payments climbs above some threshold indeed providing the payments are sufficiently generous carbon credit payment schemes offer an effective means of increasing carbon sequestration

potential pitfalls for the purchasing power parity puzzle sampling and specification biases in mean reversion tests of the law of one price the ppp puzzle is based on empirical evidence that international price differences for individual goods loop or baskets of goods ppp appear highly persistent or even nonstationary the present consensus is these price differences have a half life that is of the order of five years at best and infinity at worst this seems unreasonable in a world where transportation and transaction costs appear so low as to encourage arbitrage and the convergence of price gaps over much shorter horizons typically days or weeks however current empirics rely on a particular choice of methodology involving i relatively low frequency monthly quarterly or annual data and ii a linear model specification in fact these methodological choices are not innocent and they can be shown to bias analysis towards findings of slow convergence and a random walk intuitively if we suspect that the actual adjustment horizon is of the order of days then monthly and annual data cannot be expected to reveal it if we suspect arbitrage costs are high enough to produce a substantial band of inaction then a linear model will fail to support convergence if the process spends considerable time random walking in that band thus when testing for ppp or loop model specification and data sampling should not proceed without consideration of the actual institutional context and logistical framework of markets

forest valuation under the new zealand emissions trading scheme a real options binomial tree with stochastic carbon and timber prices under the new zealand emissions trading scheme forests planted on or after january 1 1990 earn carbon credits these credits have to be repaid when the forest is harvested this paper analyses the effects of this scheme on the value of bareland on which radiata pine is to be planted a real options method is developed and applied assuming stochastic carbon and timber prices we find that land value increases by about 73 with the optimal rotation age substantially lengthened the derived optimal harvest price thresholds are useful in deciding whether to harvest or to wait jel q23 q28

the lognormal diffusion is hardly an equilibrium price process for exhaustible resources abstract in a model of a competitive spot market for an exhaustible resource under demand uncertainty it is shown that the lognormal diffusion the geometrical brownian motion can hardly be an equilibrium price process under the reasonable assumptions that suppliers choose the time to extract and deposits have different costs each supplier will start extraction when price first exceeds a boundary which depends on that supplier s costs but no new extraction will start during periods when the price is lower than the previously recorded high it is highly unlikely that aggregate demand responds to prices in the same way as supply

when more flexibility yields more fragility the microfoundations of keynesian aggregate unemployment abstract wages are an element of cost crucially affecting the competitiveness of individual firms but the wage bill is also a crucial element of aggregate demand hence it could be that more flexible and fluid labour markets while allowing for faster inter firm reallocation of labour may also render the whole economic system more fragile more prone to recession and more volatile in this work we investigate some conditions under which such a conjecture applies the paper presents an agent based model that investigates the effects of two archetypes of capitalism in terms of regimes of labour governance defined by the mechanisms of wage determination firing labour protection and productivity gains sharing upon i labour market regularities and ii macroeconomic dynamics long term rates of growth gdp fluctuations unemployment rates inequality etc the model is built upon the keynes meets schumpeter family of models dosi et al 2010 explicitly incorporating different microfounded labour market regimes our results show that seemingly more rigid labour markets and labour relations are conducive to coordination successes leading to higher and smoother growth

smooth pasting as rate of return equalization abstract we further elucidate the smooth pasting condition behind optimal early exercise of options it is easy to show that smooth pasting implies rate of return equalization between the option and the levered position that results from exercise this yields new economic insights into the optimal early exercise condition that the option holder faces

the value of adaption climate change and timberland management abstract adaptation to exogenous change occurs on both intensive and extensive margins whether and how one accounts for human adaptation directly affects estimates of the economic consequences of environmental change estimates that are both critical in informing policy decisions and notoriously difficult to value this paper introduces and applies an analytical framework for placing an economic value on adaptation we explore the issue first in a stylized model that facilitates making concrete generalizations about the kinds of adaptations that generate high or low economic value we then test the soundness of our insights by incorporating learning and adaptive decision making into a structural dynamic forestry model where climate change is imposed exogenously and agents respond optimally using downscaled climate projections integrated with site and species specific timber productivity data we estimate the economic value of adaptation to climate change within the california timber industry we find on the intensive margin changing the rotation intervals will yield a low value of adaptation but on the extensive margin replanting more suitable tree species can yield significant value

inequality leverage and crises the paper studies how high leverage and crises can arise as a result of changes in the income distribution empirically the periods 1920 1929 and 1983 2007 both exhibited a large increase in the income share of the rich a large increase in leverage for the remainder and an eventual financial and real crisis the paper presents a theoretical model where these features arise endogenously as a result of a shift in bargaining powers over incomes a financial crisis can reduce leverage if it is very large and not accompanied by a real contraction but restoration of the lower income group s bargaining power is more effective

great recession slow recovery and muted fiscal policies in the us this paper reconsiders the role of macroeconomic shocks and policies in determining the great recession and the subsequent recovery in the us the great recession was mainly caused by a large demand shock and by the zlb on the interest rate policy in contrast with previous findings the subsequent jobless recovery is explained by the zlb effect we estimate a fraction of non ricardian households which is close to 50 and obtain comparatively large fiscal multipliers however we cannot detect a significant contribution of fiscal policies in stabilizing the us economy for instance the 2007 2009 large increase in expenditure to gdp ratios was apparently determined by the adverse non policy shocks that caused the recession

technical change sectoral dislocation and barriers to labor mobility factors behind the great recession abstract the global financial and economic crisis which began in late 2007 great recession is the worst international crisis since 1929 great depression and still affects many countries this paper attempts to determine if the theory of extended crises presented by delli gatti et al 2012 is consistent with empirical evidence the analysis is carried out using two approaches the first part of the paper is purely descriptive and is dedicated to a comparison between structural differences and different patterns of development in six countries france germany italy spain uk and us using data on the major world economies klems and stan since 1970 we show that the fundamentals behind the extended crisis theory apply to these economies we focus particularly on italy germany and the us among large economies italy is one of the most affected and still not recovering even though the italian financial sector appeared to have been less exposed to the 2008 shock than other countries the crisis in italy could be directly connected to the failure of the italian economy to move to an economic system based on more skill intensive production in particular in the service sector as in the us the us financial sector was extremely exposed to the 2008 sub prime crisis but us economy recovered much faster than in many european countries germany is the leading european economy generally considered in european public debate as the example to be followed in the last part of the paper the analysis is broadened involving more countries in a panel analysis approach different specifications of panel probit logit models are presented in a first attempt to investigate the roles of both structural features and financial shock in explaining the extent of the crisis in different countries

the tale of two great crises abstract the great depression of 1929 and the great financial crisis of 2008 have been the two big events of the last 75 years not only have they produced serious economic consequences but they also changed our view of economics and policymaking the aim of this work is to compare these two great crises and highlight similarities as well as differences monetary policy the exchange rate system and the role of banks are our fields of investigation we find interesting parallels between the two big events but also differences in their specific developments

the purchasing power parity persistence paradigm abstract rogoff journal of economic literature 1996 34 647 668 describes the remarkable consensus of 3 5 year half lives of purchasing power parity deviations among studies using long horizon data these studies however focus on rejections of unit roots in real exchange rates and do not use appropriate techniques to measure persistence our half life estimates explicitly account for serial correlation sampling uncertainty and most importantly small sample bias calculating confidence intervals as well as point estimates for long horizon and post 1973 data we find that even though most of the point estimates lie within the 3 5 year range univariate methods provide virtually no information regarding the size of the half lives

optimal adaptive price search consider the problem of a consumer desiring to buy a good which is sold at a variety of prices such a buyer will be able to obtain a sequence of price quotations from various sellers when should the buyer stop searching for a lower price if he continues he may obtain a lower price but he incurs additional time effort and expense in searching the optimal price search decision is one of balancing the expectation of a possibly lower price obtained by continued search against cumulative costs from search when the prices arise from a known probability distribution the optimal search strategy has certain well defined and desirable properties in the more realistic case that the buyer has only partial information about the price distribution and must update his beliefs after observing prices in the marketplace the problem becomes more complex and search strategies become less well behaved the major purpose of this article is to determine new conditions under which optimal policies have these desirable characteristics in the case where the consumer possesses only incomplete information about the distribution of prices price quotations he receives in addition to providing him with price possibilities provide him with information about that distribution rothschild 151 in citing an unpublished paper of gastwirth has noted that small specification errors for an assumed distribution can lead to substantial changes in expected number of searches and expected cost consequently the assumption of a known distribution of prices can have a profound effect on total cost 1 0022 053 l 8 l 040001 20 02 00 o

ppp strikes back aggregation and the real exchange rate we show the importance of a dynamic aggregation bias in accounting for the ppp puzzle we prove that the aggregate real exchange rate is persistent because its components have heterogeneous dynamics established time series and panel methods fail to control for this using eurostat data we find that when heterogeneity is taken into account the estimated persistence of real exchange rates falls dramatically its half life for instance may fall to as low as eleven months significantly below the consensus view of three to five years

trends in natural resource commodity prices deterministic or stochastic abstract the type of trend be it stochastic or deterministic exhibited by the price of a resource commodity should play a critical role in the development and empirical verification of theories which may explain its long run behavior the nature of the trend however can only be discerned through empirical testing to this end we present a menu of unit root testing procedures for characterizing observed trends in any economic time series including natural resource commodity prices we examine the prices of 11 resource commodities the evidence suggests that five price series exhibit stochastic trends while the remaining six price series appear to be stationary around a deterministic trend

the effect of mean reversion on investment under uncertainty abstract mean reverting processes are appropriate for most real option investment models yet geometric brownian motion gbm processes are generally used for tractability hassett and metcalf j econom dyn control 19 1995 1471 1488 argue that using a gbm process is justified because mean reversion has two opposing effects it brings the investment trigger closer and also reduces the conditional volatility thereby lowering the likelihood of reaching the trigger and the overall effect on investment should be negligible for most reasonable parameter values this paper extends the hassett and metcalf model by incorporating a third factor the effect of mean reversion on systematic risk the main result is that mean reversion in general does have a significant impact on investment moreover this effect could be either positive or negative depending on various factors such as project duration cost of investing interest rate etc thus it is generally inappropriate to use the gbm process to approximate a mean reverting process

options uncertainty and sunk costs an empirical analysis of land use change abstract in a real option model of land conversion incorporating return uncertainty and sunk costs optimal conversion thresholds are significantly higher than those from expected net present value models not accounting for these factors empirical tests of conversion from agriculture to forest suggest that landowners value the option to convert when making conversion decisions higher uncertainty in returns to all potential uses and lower correlation between shocks to agricultural and forest returns decreases the likelihood of conversion estimates indicate a significant impact on conversion decisions with approximations of option values ranging from 7 to 81 of the expected value of the land asset

real exchange rate behavior the recent float from the perspective of the past two centuries using annual data spanning two centuries for dollar sterling and franc sterling real exchange rates we find strong evidence of mean reverting real exchange rate behavior using simple stationary autoregressive models estimated on prefloat data we easily outperform nonstationary real exchange rate models in dynamic forecasting exercises over the recent float such stationary univariate equations explain 60 80 percent of the in sample variation in real exchange rates although the degree of short run persistence may be high the econometric estimates imply a half life of shocks to the real exchange rate of about 6 years for dollar sterling and a little under 3 years for franc sterling

asset retirement with infinitely repeated alternative replacements harvest age and species choice in forestry abstract at what age should productive assets be retired how should replacements be chosen when they differ in their uncertain ability to generate future incomes as a particular version of that problem we study the tree harvesting decision with two possible replacement species whose values as timber are stochastic and whose growth functions are deterministic in the single rotation wicksell problem starting with a bare piece of land an empty shop it is optimal to choose and plant one species immediately if its current value is sufficiently high relative to that of the other species the alternative equipment however if the species are insufficiently price differentiated it is preferable to leave the land vacant the shop empty despite the opportunity cost of doing so in the repeated version of the problem it is never optimal to leave the land bare provided the cost of replacement is null furthermore the optimal harvest tree retirement age not only depends on the price and current productivity of the trees in place but also on the price and productivity of the other species because it may replace the current one the harvest age reaches a peak at some critical threshold of the relative price that signals the necessity to switch to the alternative species indeed this is when the opportunity cost of choosing one alternative replacement over the other is the highest the land value and also the value of the firm is similar to an american option with free boundary infinite expiry period and endogenous payoff the paper highlights the opportunity cost of alternative replacement options and the central role of their volatility in both asset retirement and replacement choice decisions all results are derived analytically a numerical treatment by the penalty method completes the resolution

investment under alternative return assumptions comparing random walks and mean reversion abstract many recent theoretical papers have come under attack for modeling prices as geometric brownian motion this process can diverge over time implying that firms facing this price process can earn infinite profits we explore the significance of this attack and contrast investment under geometric brownian motion with investment assuming mean reversion while analytically more complex mean reversion in many cases is a more plausible assumption allowing for supply responses to increasing prices we show that cumulative investment is generally unaffected by the use of a mean reversion process rather than geometric brownian motion and provide an explanation for this result

estimating the influence of u s ethanol policy on plant investment decisions a real options analysis with two stochastic variables abstract u s ethanol policies have contributed to changes in the levels and the volatilities of revenues and costs facing ethanol firms the implications of these policies for optimal investment behavior are investigated through an extension of the real options framework that allows for the consideration of volatility in both revenue and cost components as well as the correlation between them the effects of policy affecting plant revenues dominate the effects of those policies affecting production costs in the absence of these policies much of the recent expansionary periods would have not existed and market conditions in the late 1990s would have led to some plant closures we also show that regardless of plant size u s ethanol policy has narrowed the distance between the optimal entry and exit curves implying a more narrow range of inactivity and indicative of a more volatile evolution for the industry than would have existed otherwise

inequality credit and financial crises in the three decades leading up to the financial crisis of 2008 09 income inequality rose across much of the developed world this has led to a vigorous debate as to whether widening inequality was somehow to blame for the crisis by driving private sector credit booms despite growing interest empirical evidence on an inequality fragility relationship is limited based on a panel analysis of 18 oecd organisation for economic co operation and development countries for the years 1970 2007 this study provides evidence of a positive relationship between income concentration and private sector indebtedness once other traditional drivers are controlled for if confirmed the implications of this result are as follows i the view that the distribution of income is irrelevant to macroeconomic stability as implicit in mainstream approaches needs further investigation and ii in order to make the financial system more robust policy makers should cast the net wider than monetary policy and regulatory reforms and consider the effects of changes to distributive patterns

wicksellian theory of forest rotation under interest rate variability abstract we apply the wicksellian single rotation framework to cover the unexplored case of variable and stochastic interest rate we provide a mathematical characterization of the two dimensional optimal stopping problem and show in the presence of amenity valuation that increased interest rate volatility lengthens the optimal rotation period and increases the value of the optimal policy by modelling the interest rate as a mean reverting process and forest value as a geometric brownian motion and abstracting from amenity valuation we present an explicit solution for the problem numerical illustrations indicate that interest rate volatility has a significant and non linear impact on optimal rotation

on solving the multirotational timber harvesting problem with stochastic prices a linear complementarity formulation this article develops a two factor real options model of the harvesting decision over infinite rotations assuming a known stochastic price process and using a rigorous hamilton jacobi bellman methodology the harvesting problem is formulated as a linear complementarity problem that is solved numerically using a fully implicit finite difference method this approach is contrasted with the markov decision process models commonly used in the literature the model is used to estimate the value of a representative stand in ontario s boreal forest both when there is complete flexibility regarding harvesting time and when regulations dictate the harvesting date

the great depression versus the great recession in the u s how fiscal monetary and financial polices compare abstract this study reviews the financial distress that triggered and amplified the financial crises of the great depression and great recession and compares macroeconomic and financial policy responses shadow banking funded the build up of the financial excesses that preceded both the quicker and forceful response of monetary and fiscal policy during the great recession and stronger action to restore market functionality mitigated the downturn and aided recovery nevertheless actions to address the mortgage debt overhang were slower post depression reforms focused on preventing deposit runs and post great recession reforms on preventing runs on bank debt and shadow banks while boosting capital buffers

a stochastic analysis of the tree paradigm abstract the tree paradigm which is a problem in optimal stopping has important ramifications for human capital acquisition search behavior firm entry and in the theory of renewable resources our paper extends previous work in the stochastic literature on several fronts we exhibit a tractable solution to the rotation problem for the stochastic model analyze the effects of inputs which control the growth process and illustrate our results with a multi stage learning problem

taxation and rotation age under stochastic forest stand value abstract the paper uses both the single rotation and ongoing rotation framework to study the impact of yield tax lump sum tax and tax on interest rate earnings on the privately optimal rotation period when forest stand value is stochastic and forest owners are risk averse or risk neutral under risk aversion the optimal harvesting threshold is lower and therefore the expected rotation period shorter than under risk neutrality both in the single and ongoing rotation cases whether the forest owner is risk averse or risk neutral a higher yield tax a higher lump sum tax or a higher tax on interest rate earnings raise the optimal harvesting threshold numerical results indicate that the optimal harvesting threshold increases less rapidly under risk aversion than under risk neutrality with an increase in either a yield tax or the volatility of forest stand value

non renewability in forest rotations implications for economic and ecosystem sustainability abstract the forest rotations problem has been considered by generations of economists fisher 1930 boulding 1966 samuelson 1976 traditionally the forest resource across all future harvest periods is assumed to grow without memory of past harvest periods this paper integrates economic theory and intertemporal ecological mechanics linking current harvest decisions with future forest growth financial value and ecosystem health results and implications of a non renewable forest resource and the influence of rotation length and number on forest recovery are reported cost estimates of moving from short term economic rotations to long term ecological rotations suggest the level of incentive required for one aspect of ecosystem management a net private cost of maintaining ecosystem health emerges and for public policy purposes can be compared with measures of non timber amenity values and social benefits exhibiting increasing returns to rotation length

good timing the economics of optimal stopping abstract this paper presents an economic interpretation of the optimal stopping of perpetual project opportunities under both certainty and uncertainty prior to stopping the expected rate of return from delay exceeds the rate of interest the expected rate of return from delay is the sum of the expected rate of change in project value and the expected rate of change in the option premium associated with waiting at stopping the expected rate of return from delay has fallen to the rate of interest viewing stopping in this way unifies the theoretical and practical insights of the theory of stopping under certainty and uncertainty

the micro macro disconnect of purchasing power parity abstract this paper reconciles the persistence of aggregate real exchange rates with the faster adjustment of international relative prices in microeconomic data error correction model estimates indicate that a different mix of shocks drives international price deviations at the microeconomic level and that dynamic adjustment works through arbitrage in the goods market rather than the foreign exchange market when half lives are estimated conditional on a common set of estimated macro shocks we find that micro relative prices exhibit every bit as much persistence as aggregate real exchange rates these results challenge theories of real exchange rate persistence based on sticky prices and heterogeneity across goods

a markup interpretation of optimal investment rules we re examine the basic investment problem of deciding when to incur a sunk cost to obtain a stochastically fluctuating benefit the optimal investment rule satisfies a trade off between a larger versus a later net benefit we show that this trade off is closely analogous to the standard trade off for the pricing decision of a firm that faces a downward sloping demand curve we reinterpret the optimal investment rule as a markup formula involving an elasticity that has exactly the same form as the formula for a firm s optimal markup of price over marginal cost this is illustrated with several examples consider what is probably the most basic irreversible investment problem a project can be undertaken that requires a sunk cost c and yields a benefit v the cost is known and constant over time but the benefit measured as the present value at the time the cost is incurred fluctuates as an autonomous markov process vt with continuous sample paths time is continuous and

regime switching in stochastic models of commodity prices an application to an optimal tree harvesting problem abstract this paper investigates whether a regime switching model of stochastic lumber prices is better for the analysis of optimal harvesting problems in forestry than a more traditional single regime model prices of lumber derivatives are used to calibrate a regime switching model with each of two regimes characterized by a different mean reverting process a single regime mean reverting process is also calibrated the value of a representative stand of trees and optimal harvesting prices are determined by specifying a hamilton jacobi bellman variational inequality which is solved for both pricing models using a implicit finite difference approach the regime switching model is found to more closely match the behavior of futures prices than the single regime model in addition analysis of a tree harvesting problem indicates significant differences in terms of land value and optimal harvest thresholds between the regime switching and single regime models

dissecting the ppp puzzle the unconventional roles of nominal exchange rate and price adjustments the conventional view as expounded by sticky price models is that price adjustment determines the ppp reversion rate this study examines the mechanism by which ppp deviations are corrected nominal exchange rate adjustment not price adjustment is shown to be the key engine governing the speed of ppp convergence moreover nominal exchange rates are found to converge much more slowly than prices with the reversion being driven primarily by nominal exchange rates real exchange rates also revert at a slower rate than prices as identified by the ppp puzzle j econ lit 34 1996 647 c 2003 elsevier b v all rights reserved

the effect of catastrophic risk on forest investment decisions abstract we analyze the effect of catastrophic risk on forest investment decisions by employing a forest level model where the output price is specified to follow a stochastic process we then incorporate a poisson jump process to reflect the occurrence of catastrophic events it is found that the presence of catastrophic risk always results in a reduced production value but an increased investment threshold for a forestry project however depending on the assumption regarding the option whether the right to invest can be maintained after the occurrence of such an event the degree and pattern of the effect are different

conditional ppp and real exchange rate convergence in the euro area abstract while economic theory highlights the usefulness of flexible exchange rates in promoting adjustment in international relative prices flexible exchange rates also can be a source of destabilizing shocks we find that when countries joining the euro currency union abandoned their national exchange rates the adjustment of real exchange rates toward their long run equilibrium surprisingly became faster to investigate we distinguish between differing rates of purchasing power parity ppp convergence conditional on alternative shocks which we refer to as conditional ppp we find that the loss of the exchange rate as an adjustment mechanism after the introduction of the euro was more than compensated by the elimination of the exchange rate as a source of shocks in combination with faster adjustment in national prices these findings support claims that flexible exchange rates are not necessary to promote long run international relative price adjustment

revisiting the persistence of real exchange rates abstract in this paper we provide new and robust evidence that panel regressions significantly reduce the estimated half lives of real exchange rates in a sample of 21 countries these results are obtained under dynamic panel models that control for non purchasing power parity ppp equilibria small sample bias does not have a significant impact on half lives since the increase in the half life arising from the bias is more than compensated by the decrease of the half life due to the control of non ppp equilibria among the two sources of non ppp equilibria i e first the balassa samuelson effect and second smooth shifts in mean we find that under a heterogeneous panel model the first source results in a larger reduction of half lives

optimal forest rotation and land values under a borrowing constraint abstract this study relaxes the assumption of perfect capital markets in the classical faustmann forest rotation model a constraint on borrowing changes all the basic properties of optimal forest harvesting instead of a constant rotation period an infinite chain of rotations is determined by a nonlinear difference equation the rotation period evolves over time and approaches a stationary rotation in finite or infinite time the length of optimal rotation timber supply and the value of forest land depend on forest owner specific factors that are normally nonexistent in rotation problems the model explains several empirical findings that cause problems for the classical versions of the faustmann model

the financial accelerator in an evolving credit network we model a credit network characterized by credit relationships connecting i downstream d and upstream u firms and ii firms and banks the net worth of d firms is the driver of fluctuations the production of d firms and of their suppliers u firms in fact is constrained by the availability of internal finance proxied by net worth to the d firms the structure of credit interlinkages changes over time due to an endogeneous process of partner selection which leads to the polarization of the network at the aggregate level the distribution of growth rates exhibits negative skewness and excess kurtosis when a shock hits the macroeconomy or a significant group of agents in the credit network a bankruptcy avalanche can follow if agents leverage is critically high in a nutshell we want to explore the properties of a network based financial accelerator

the valuation of forestry resources under stochastic prices and inventories a contingent claims approach to capital budgeting may be preferable to traditional methods where uncertainty and managers strategic reactions to changing conditions are impor tant as an example of such a case we solve the classical problem of the duration of an investment in forestry resources i e when to cut down the trees in the general case of stochastic output prices and stochastic natural growth rate and timber inventories a con tingent claims approach is used to value the forestry resources as a function of 1 sto chastic prices and inventories and 2 an asymmetric optimal production policy that incorporates the option to halt timber production temporarily i introduction classical capital budgeting techniques are based on the assumption that fu ture cash flows follow a rigid pattern and can be accurately predicted far into the future on the basis of such cash flow predictions the project is either accepted or rejected the uncertainty in the project and management s strategic reactions to changing conditions are dealt with only superficially at best a risk adjusted interest rate is employed and various deterministic scenarios are plotted out in situations where uncertainty and management s strategic reactions to it are im portant the classical technique is apt to lead to wrong decisions the technology needed to deal with such problems more accurately is becoming available the purpose of this paper is to present a stylized example of how it can be used our example is a general solution to the classical duration problem of the optimal control of a long term renewable resource investment such as forestry resources i e when to chop down a tree 1 if the prices and the natural growth rate of the inventory of forest timber are assumed to be deterministic the optimal control is very simple to derive but when both the price and inventory of timber are stochastic the problem becomes both stochastic and asymmetric the asym

harvesting a renewable resource under uncertainty abstract this paper presents a theory of harvesting that allows for partial harvests and accounts for the risk of extinction for biological assets with size dependent stochastic growth the harvesting decision is formulated as a disinvestment problem in continuous time and generalized faustmann formulas are derived the probability of extinction is then analyzed for a wide class of growth functions an illustration based on the logistic brownian motion shows that both optimal biomass at harvest and harvest size do not vary monotonically with uncertainty more generally this paper illustrates the importance of properly accounting for barriers in stochastic investment problems

liquidity traps and large scale financial crises this paper estimates a nonlinear threshold var to investigate if a keynesian liquidity trap due to a speculative motive was in place in the u s great depression and the recent great recession we find clear evidence in favor of a breakdown of the liquidity effect after an unexpected increase in m2 in the 1921 1940 period this evidence which is consistent with the keynesian view on a liquidity trap is shown to be state contingent in particular it emerges only when a speculative regime identified by high realizations of the dow jones index is considered a standard linear framework is shown to be ill suited to test the hypothesis of a keynesian liquidity trap an investigation performed with the same data for the period 1991 2010 confirms the presence of a liquidity trap just in the speculative regime this last result emerges significantly only when we consider the federal funds rate as the policy instrument and we model the divisia m2 measure of liquidity

the stochastic rotation problem a generalization of faustmann s formula to stochastic forest growth abstract in the present paper we study the optimal cutting strategy 1 2 for an ongoing forest by using stochastic impulse control we show how faustmann s formula can be generalized to stochastic growing forests the paper extends and clarifies previous studies by miller and voltaire 1983 clarke and reed 1989 and reed and clarke 1990

principles of stochastic dynamic optimization in resource management the continuous time case abstract a wide range of problems in economics agriculture and natural resource management have been analyzed using continuous time optimal control models where the state variables change over time in a stochastic manner using a firm level investment model and a model of environmental degradation this paper provides a concise introduction to continuous time stochastic control techniques the process used to derive the differential of a stochastic process is stressed and in turn is used to explain ito s lemma bellman s equation the hamilton jacobi equation the maximum principle and the expected dynamics of choice variables a basic extension of the dynamic duality literature is also provided where the hamilton jacobi equation is used to derive a stochastic and dynamic analogue of hotelling s lemma

official exchange rate arrangements and real exchange rate behavior we study the behavior of real exchange rates under various official designations of exchange rate arrangements examining many currencies we find important differences across the designations most notably real exchange rate mean reversion is fastest when nominal exchange rates are officially pegged we also find a large nonlinear effect adjustment is fastest when the real exchange rate deviates greatly from its mean this nonlinear effect is also most striking among officially pegged currencies finally we find that nominal exchange rates rather than prices do most of the adjusting

informational efficiency of markets for stumpage comment in a study of the information efficiency of markets for stumpage in the southern united states washburn and binkley found that time series data on stumpage price if given on annual or quarterly bases reveal weak form information efficiency for stumpage markets from this they conclude that there can be no gain from using past price movements to play the market in timing timber harvests p 403 specifically they infer that the reservation price rules derived for optimal forest harvesting by norstrom lohmander and brazee and mendelsohn are not applicable to the management of southern pine timberlands

deviations from purchasing power parity under different exchange rate regimes do they revert and if so how abstract we propose an empirical model for deviations from long run purchasing power parity ppp that simultaneously accounts for three key features i adjustment toward ppp may occur via nominal exchange rates and relative prices at different speeds ii different exchange rate regimes may generate regime shifts in the structural dynamics of ppp deviations iii nonlinear reversion toward ppp in response to shocks this empirical framework encompasses and synthesizes much previous empirical research using over a century of data for the g5 countries we provide evidence that long run ppp holds the relative importance of nominal exchange rates and prices in restoring ppp varies over time and across different exchange rate regimes and reversion to ppp occurs nonlinearly at a speed that is fairly consistent with the nominal rigidities suggested by conventional open economy models

on the elasticities of harvesting rules abstract in this paper we rank the relative importance of the exogenous parameters upon the optimal harvesting size in a stochastic rotation problem we show that when the tree growth follows geometric brownian motion the harvesting size is most elastic to the harvesting cost followed by the interest rate and is least elastic to the parameters of tree growth similar ranking holds for the linear growth case in both cases the harvesting size is increasing and concave in the harvesting cost bounded between two parallel lines the harvesting decision is made according to a stochastic extension of the faustmann formula

debt deflation financial market stress and regime change evidence from europe using mrvar the economic meltdown since 2008 9 has created disinflation and even deflation in some countries in the euro area in a period with large debt overhang creating the condition for a continuing financial market stress in the euro area as disinflation and deflation push up the real interest rate while growth and income declines the leveraging problem becomes more severe and the economy risks shifting into a regime with high insolvency risk high financial stress rising credit spreads possibly accompanied by strong adverse macroeconomic feedback loops investigating the consequences of those magnifying feedback loops given the debt deflation we demonstrate the possibility of unstable dynamics and downward spirals in the presence of regime dependent macro feedback loops using a theoretical model with decentralized matching mechanisms on both labor and financial markets to explore the amplifying linkages between deflation output labor and financial markets we employ a new solution procedure called nmpc to solve our models variants for out of steady state dynamics we empirically explore deflationary trends in europe and employ a global var gvar model for a large euro area macro data set to estimate the impact of deflation on output moreover we use a four variable multi regime var mrvar model with regime dependent irs to study deflationary as well as well as the financial risk drivers in a mrvar setting new measures for financial risk drivers are employed and multi regime irs for output inflation rates interest rates and financial stress are explored we also study regime changes in central macro relationships such as regime change in the credit output link the phillips curve and in okun s law

mussa redux and conditional ppp abstract the extreme persistence of real exchange rates found commonly in post bretton woods data does not hold in the preceding fixed exchange rate period when the half life was roughly half as large in our sample this finding supports sticky price models as an explanation for real exchange rate behavior extending the classic argument of mussa 1986 from a focus on short run volatility to long run dynamics two thirds of the rise in real exchange rate variance observed across exchange rate regimes is attributable to greater persistence of responses to shocks including greater price stickiness rather than to greater variance of shocks themselves

the optimal production of an exhaustible resource when price is exogenous and stochastic this paper examines the optimal production of a resource such as oil when its price is determined exogenously e g by a cartel such as opec and is subject to stochastic fluctuations away from an expected growth path we first examine the dependence of production on extraction cost and show that the conventional exponential decline curve is indeed optimal if marginal cost is constant with respect to the rate of extraction but is a hyperbolic function of the reserve level we next show that uncertainty about future price affects the optimal production rate in two ways first if marginal cost is a convex concave function of the rate of production stochastic fluctuations in price raise lower average cost over time so that there is an incentive to speed up slow down production second the option value of the reserve i e the ability to withhold production indefinitely and never incur the cost of extraction provides an incentive to slow down the rate of production

money and velocity during financial crises from the great depression to the great recession abstract this study models the demand for a broad monetary aggregate m2 from the great depression through the great recession key to the model is the interaction between a measure of time variation in economic agents perceived financial risk and an index of the cost of portfolio adjustment the finding of a useful money demand relationship suggests that skepticism regarding the indicator role of a broad liquid money aggregate as a policy guide may be exaggerated further our model provides some guidance for policymakers who face the challenge of unwinding large balance sheets as risk premia return to normal and velocity adjusts

harvest decisions and asset valuation for biological resources exhibiting size dependent stochastic growth optimal harvest rules and preharvest valuation procedures are derived for biological assets with stochastic size dependent growth in a stochastic price environment these issues are analyzed as continuous time optimal stopping problems both the single rotation and ongoing rotations problems are addressed the sensitivity of harvest and valuation rules is assessed the results are compared with those derived from a myopic look ahead procedure and with the corresponding findings for age dependent growth copyright 1990 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

an extreme value analysis of the last century crises across industries in the u s economy the two large scale crises that hit the world economy in the last century i e the great depression and the great recession have similar outbreak and recovery patterns with respect to several macroeconomic variables in particular the largest depressions are likely to be accompanied by stock market crashes this study investigates the behavior of the u s stock market before during and after deep downturns focusing particularly on the tails of the return distribution we develop two automatic procedures to identify multiple change points in the tail of financial time series as well as in the co crash and co boom probabilities of different markets we then apply our methodology to twelve time series representative of the sectors of the u s economy we find that regime shifts in the lower tail of the distribution tend to co occur before deep downturns our results contribute to a better understanding of the origin and systemic nature of large scale events to make policy interventions more timely and effective

a comparison of the ito and stratonovich formulations of problems in finance abstract a comparison of and the relationship between the ito and stratonovich formulations of stochastic integration is given it is argued that generally the ito formulation is appropriate for problems of finance and economics the black scholes option pricing problem is discussed in both frameworks with the ito formulation being shown to be clearly superior a finance example in which the stratonovich approach is simplest is also presented

optimal forest rotation when stumpage prices follow a diffusion process a key assumption in the faustmann rule for financial maturity is that stumpage prices are constant over time timber price series however exhibit wide fluctuations over time which this paper models as a lognormal diffusion process comparing the diffusion results modeled here to the fixed price faustmann results show 1 the prescribed rotation length is generally longer 2 computed stand values are higher using the diffusion model with the greatest divergence occurring when a stand is about the midpoint of a rotation 3 as the stumpage price volatility increases the gain in computed npv increases though in a nonlinear fashion

mean reversion in equilibrium asset prices evidence from the futures term structure we use the term structure of futures prices to test whether investors anticipate mean reversion in spot asset prices the empirical results indicate mean reversion in each market we examine for agricultural commodities and crude oil the magnitude of the estimated mean reversion is large for example point estimates indicate that 44 percent of a typical spot oil price shock is expected to be reversed over the subsequent eight months for metals the degree of mean reversion is substantially less but still statistically significant we detect only weak evidence of mean reversion in financial asset prices in this study we provide evidence of mean reversion in the prices of several real and financial assets rather than examining evidence of ex post reversion using time series of asset prices we use price data from futures contracts with varying delivery horizons to test whether investors expect asset prices to revert this approach offers two advantages first since futures prices are readily available for many markets our procedure can be implemented for many assets including those for which reliable spot price data is elusive second there is little ambiguity as to the source of any mean reversion detected using our method subject only to the maintained assumption that the no arbitrage cost of carry condition holds our test detects mean reversion that is expected to occur in equilibrium but has no power to detect mean reversion resulting from noise or inefficiencies our methodology focuses on relations between price levels and the slope of the futures term structure defined as the change across delivery dates in the futures prices observed on a given trading date an inverse relation between prices and the futures term slope constitutes evidence that investors expect mean reversion in spot prices to illustrate initially assume there are no

thinning and harvesting in stochastic forest models abstract this paper analyzes a stochastic forest growth model in which the manager is able to first thin the forest to promote better growth before harvesting both wicksell single thinning and harvesting cycle and faustmann on going rotation problems are considered the wicksell problem is analyzed by first restricting the class of decision times to thinning harvesting pairs that bound the growth away from infinity and imbedding the problem in an infinite dimensional linear program on a space of triplets of measures these measures capture the thinning and harvesting decisions along with the behavior of the growth process prior to harvest an auxiliary linear program then leads to a nonlinear optimization problem for which an optimal value and solution are determined the values of all the problems are be related through a set of inequalities the solution of the nonlinear problem determines random thinning and harvesting times for the single thinning and harvesting cycle which demonstrate the equality of the values of these various problems finally for the wicksell problem the unrestricted class of thinning and harvest times is shown to give the same value as the restricted class the faustmann on going thinning and harvesting rotation problem is reduced to a wicksell problem which then allows for the characterization of the value as the solution to a different nonlinear optimization problem the effects of the opportunity to thin the forest are illustrated on a mean reverting stochastic model

entry and exit decisions based on a discount factor approach abstract entry and exit decisions under price uncertainty are discussed by a discount factor approach to investment the approach makes it possible to express the value of the firm as a function of a set of trigger prices at which investment takes place and to determine the optimal policy by simple maximization starting with a standard entry exit model by dixit 1989 entry and exit decisions under uncertainty journal of political economy 97 3 620 638 the paper expands to construction and scrapping decisions investment lags diminishing production capacity and limits to the number of lay up periods economic implications are investigated using experimental data and empirical shipping data

harvesting and recovery decisions under uncertainty abstract a stochastic forest rotation model in the faustmann tradition is presented and exemplified the model combines harvesting decisions with the potential to recover or clean up to restore the land after very unfavorable evolutions of the stochastic growth process uncertainty is shown to have a generally ambiguous effect on the optimal choice of investment strategy it is also shown how such models can be related to theory of optimal inventory control

the dynamic behavior of efficient timber prices a simple theoreticalmodel of a tim consist ing of faustmann rotations evalubermarket finds that there exists a rational expecta ated at the mean of the price process tions equilibrium in which prices evolve according the central question addressed in this to a stationary a r 1 process simulations analyz e study is what is the appropriate model of a model with a more general representation of tim timber prices this is an important quesber stock dynamics implications for the optimal tion given the prescriptive nature of the harvesting literature are 1 market efficiency pro timber harvesting literature3 vides little justification for random walk prices 2 and evidence unit root tests used in previous studies to analyz e that the form of the price process strongly the informational efficiency of timber markets do influences the performance of a reservanot distinguish between efficient and inefficient tion price rule relative to the faustmann markets and 3 failure to recognize asymmetric rotation haight and holmes 1991 plandisturbances in time series analyses of historical tinga 1998 nonetheless most authors aptimber prices can lead to sub optimal harvesting pear to select the form of the price process rules

real exchange rate adjustment in and out of the eurozone it is often suggested that currency unions unduly inhibit the efficient adjustment of real exchange rates recently this has been seen as a key failure of the eurozone this paper presents evidence that throws doubt on this conclusion our evidence suggests that real exchange rate movement within the eurozone was at least as compatible with efficient adjustment as the behavior of real exchange rates for the floating rate countries outside the eurozone this interpretation is consistent with a model in which nominal exchange rate movements give rise to persistent deviations from the law of one price in traded goods

bad news in the great depression the great recession and other u s recessions a comparative study in economic recessions consumption usually drops in tandem with other aggregate quantities as output or employment following the permanent income hypothesis these drops can be rationalized by the idea that consumers have pessimistic views about their long run income using a standard signal extraction model we show that this pessimism can be due either to a persistent fall of aggregate productivity before and during the recession signaling a future decline of income or to other negative information unrelated to contemporaneous fundamentals which we label bad news we classify u s recessions from 1919 to 2015 according to a bad news index reflecting this negative information we find that both the great depression and the great recession score highest in this index the index is such that we can rule out that this is due merely to the length or the depth of these recessions instead these two recessions are similar in that both were aggravated by a wave of pessimism about future income which cannot be related to contemporaneous fundamentals

a real options approach to the valuation of a forestry investment abstract the theory of real options is used to model the optimal tree harvesting decision the value of the option to harvest is estimated using a dynamic programming approach and a general numerical solution technique suitable for any type of stochastic process for prices the conditions under which the optimal harvest time is independent of price are examined in addition the impact of assuming future lumber prices are mean reverting is considered it is found that option value and optimal cutting time are significantly different under the mean reversion assumption compared to geometric brownian motion

mobility constraints productivity trends and extended crises abstract in this paper we propose an interpretation of the current global financial crisis which emphasizes sectoral dislocation following localized technical change in the presence of barriers to labor mobility this tale is reminiscent of a similar tale concerning the great depression in the 30s technical change was localized in agriculture where income fell because rising productivity could not be offset by a shrinking labor force due to the costs of moving out of agriculture for unemployed workers inelastic demand for agricultural output meant that as output increased income declined as individual incomes fell below the level necessary to finance the transition to manufacturing excess labor became trapped in agriculture reducing wages and exacerbating the rise in output shrinking incomes in agriculture reverberated on the other sectors mainly manufacturing causing a large depression nowadays it is manufacturing that plays the role of epicenter of technical change falling incomes in manufacturing yield a lack of demand for goods produced in the rest of the economy namely the service sector this may be the deep rooted cause of the long lasting slump and the painfully slow recovery

the decision to conserve or harvest old growth forest abstract the decision to harvest or conserve old growth forest is formulated as a stochastic decision problem in continuous time uncertainty in future amenity values for standing forest and in future timber revenues for harvested forest are included in the model along with the risk of catastrophic destruction by fire pest infestation etc it is shown how the decision problem can be expressed as an optimal stopping problem which can be solved analytically the optimal decision rule is shown to depend on how the ratio of current timber value to the current expected present value of amenity benefits foregone through harvesting compares with some critical level the effects of changes in uncertainty and other parameters on the optimal rule are discussed also it is shown how the cost benefit analysis and certainty equivalence procedures lead to premature harvesting and the expected loss in survival time for these sub optimal procedures is calculated