one security many markets determining the contributions to price discovery when homogeneous or closely linked securities trade in multiple markets it is often of interest to determine where price discovery the incorporation of new information occurs this article suggests an econometric approach based on an implicit unobservable efficient price common to all markets the information share associated with a particular market is defined as the proportional contribution of that market s innovations to the innovation in the common efficient price applied to quotes for the thirty dow stocks the technique suggests that the preponderance of the price discovery takes place at the new york stock exchange nyse a median 92 7 percent information share although most of the classic paradigms in market microstructure concern a security that trades in a single centralized market such situations are becoming increasingly rare in practice fragmentation the dispersal of trading in a security to multiple sites has emerged as a dominant institutional trend this process is of concern to financial economists and regulators because price information and price discovery the impounding of new information into the security price arguably the most important products of a security market have many attributes of public goods as the process of fragmentation accelerates it may be important to determine where the price information and price discovery are being produced 1 this paper suggests a practical econometric approach to this problem the technique is illustrated with an application to u s equity markets many stocks listed on the new york stock exchange nyse trade concurrently on the regional exchanges and the national association of securities dealers national market system nasd nms since a share of ibm stock is the same security whether purchased on the midwest or pacific exchange this is a particularly clear instance of multiple markets nevertheless the expres

trading and pricing in upstairs and downstairs stock markets we provide empirical evidence on the economic benefits of negotiating trades in the upstairs trading room of brokerage firms relative to the downstairs market using helsinki stock exchange data we find that upstairs trades tend to have lower information content and lower price impacts than downstairs trades this is consistent with the hypotheses that the upstairs market is better at pricing uninformed liquidity trades and that upstairs brokers can give better prices to their customers if they know the unexpressed demands of other customers we find that these economic benefits depend on price discovery occurring in the downstairs market copyright 2002 oxford university press

analytical approximations in models of hysteresis decisions made under ongoing uncertainty and costly reversibility entail a range of the state variable where inaction is optimal which in turn produces hysteresis permanent effects of temporary shifts the range is usually defined by non linear equations that need numerical solutions in this paper a technique of analytical approximations is developed and applied to two models menu costs and investment the resulting explicit solutions help clarify why hysteresis is important even for small irreversibility in the menu cost model hysteresis is two orders of magnitude larger than under the akerlof yellen or mankiw assumptions when decisions that are costly to reverse are made under conditions of ongoing uncertainty the optimum policy usually entails a range of inertia the action should be taken only when the value of the underlying state variable becomes especially favourable and reversed only when it becomes especially unfavourable there is an intermediate range over which inaction is optimal this in turn gives rise to hysteresis starting from a value in the range of inertia if the state variable crosses the action trigger point and then returns to its original level the action will be taken but not reversed thus a temporary change will leave a permanent effect numerical solutions for models of irreversible investment show that the range of inaction is remarkably large even when the cost of reversal is small see brennan and schwartz 1985 constantinides 1986 and dixit 1989a b for examples of this unfortunately the equations tlhat determine the optimum policy are highly non linear they do not have analytical solutions therefore we lack a clearer and more general understanding of why hysteresis is numerically so important in this paper i derive analytical approximations for the solutions of more general problems of this kind when the costs of change are small the idea that small costs of change induce large amounts of inertia has been popularized in the model of akerlof and yellen 1985 mankiw 1985 and others in these models second order small costs of making price changes yield price stickiness in response to first order changes in the money supply this is a simple application of the envelope theorem but these models are static and their application to a dynamic reality must assume either permanent shocks or static expectations when there is ongoing uncertainty which is rationally expected by the decision maker the option value of the status quo enlarges the zone where inaction is optimal adding these features to the mankiw akerlof yellen may model i show that fourth order small costs of change generate first order inertia

does opec influence crude oil prices testing for co movements and causality between regional crude oil prices using high frequency data the co movements among crude oil prices are analysed in order to address the question of regionalization of the world crude oil market time series econometrics in the form of error correction modelling is applied for daily crude oil price data covering the time period 1988 to 2004 and in this framework topics like weak and strong exogeneity among three major oil prices represented by brent opec and texas wti are addressed the empirical results are that causality is most likely bi directional among these crude oil prices and hence rejecting a regionalization hypothesis of the global oil market and also an influence from the opec oil price towards bent and wti which are usually claimed to have a benchmark role

price elasticities and demand side real rigidities in micro data and in macro models abstract high degrees of demand side real rigidities are able to generate the large monetary non neutrality found in aggregate data this paper provides micro based evidence on the key parameters governing this rigidity using european homescan data we find strong evidence for demand side real rigidity which is however significantly lower than that normally assumed in macro models in a menu cost model calibrated to our estimates we show that these estimates are associated with reasonable values for production side parameters but they are not able to generate the degree of monetary non neutrality observed in macro data

a new way of measuring the wti brent spread globalization shock persistence and common trends abstract the standard cointegration and the persistence of the spread of the brent wti price have been widely analyzed however no studies have been able to present evidence of both issues jointly so far a novel focus is presented in this paper from the application of the fractionally cointegrated vector autoregressive fcvar approach which allows the rigidity of the standard cointegration to be solved as result of the application of the fcvar model we identify several degrees of globalization by analyzing the order of integration of the error correction term indeed by using permanent transitory decomposition analysis we present what drives the relationship between both oil crude prices information the findings shown here reveal that the brent wti market is strongly globalized nevertheless the brent wti price spread follows a long memory process and the brent drives the brent wti price structure these results sustain some corollaries on economic policies for economic agents policy makers and business operators

menu costs and phillips curves this paper develops a model of a monetary economy in which individual firms are subject to idiosyncratic productivity shocks as well as general inflation sellers can change price only by incurring a real menu cost we calibrate this cost and the variance and autocorrelation of the idiosyncratic shock using a new u s data set of individual prices due to klenow and kryvtsov the prediction of the calibrated model for the effects of high inflation on the frequency of price changes accords well with international evidence from various studies the model is also used to conduct numerical experiments on the economy s response to various shocks in none of the simulations we conducted did monetary shocks induce large or persistent real responses

price setting with menu cost for multi product firms we model the decisions of a multiproduct firm that faces a fixed menu cost once it is paid the firm can adjust the price of all its products we characterize analytically the steady state firm s decisions in terms of the structural parameters the variability of the flexible prices the curvature of the profit function the size of the menu cost and the number of products sold we provide expressions for the steady state frequency of adjustment the hazard rate of price adjustments and the size distribution of price changes all in terms of the structural parameters we study analytically the impulse response of aggregate prices and output to a monetary shock the size of the output response and its duration both increase with the number of products they more than double as the number of products goes from 1 to 10 quickly converging to the response of taylor s staggered price model

trends and contagion in wti and brent crude oil spot and futures markets the role of opec in the last decade abstract this article examines the interconnectedness of wti and brent prices on different resolutions of price movements firstly within a multivariate bekk framework we identify high but volatile correlations with recurring highs around 0 8 and multiple periods of decoupling opec meetings increase the correlation in the short run secondly linear l1 trends reveal that long term movements of wti and brent are driven by the same dynamics confirming the one great pool hypothesis opec meetings have only little impact on long term price trends thirdly we find leading effects of wti over brent by short term trends of several days especially in a negative direction these trends have an asymmetrical effect on volatility negative trends cause a stronger increase than positive trends these findings are of interest to policy makers as well as hedging strategies of crude oil portfolios and provide insight into long term movements of crude prices

durable goods an explanation for their slow adjustment at the microeconomic level durable purchases are often discontinuous and relatively large this feature has the potential to explain why aggregate expenditure on durables responds only slowly relative to the frictionless permanent income model to wealth and other aggregate innovations in this paper i develop new results on the problem of dynamic aggregation of stochastically heterogeneous units which help to characterize the connection between microeconomic behavior and aggregate dynamics in the presence of nonconvex adjustment costs using these results and splitting postwar u s aggregate durable purchases into different subcategories and time periods i provide further support for the view that lumpy microeconomic purchases play an important role in explaining the time series behavior of aggregate expenditure on durable goods

rational inattention in uncertain business cycles the paper proposes endogenous information choice as a channel through which uncertainty affects price dynamics i consider a rational inattention model with volatility uncertainty and endogenous information processing capability according to the model firms learning and optimal attention exhibits inertia and asymmetry in response to volatility changes firms choose to process more information when uncertainty rises especially about aggregate conditions and their pricing behavior changes accordingly using a markov switching factor augmented vector autoregression ms favar the paper also documents a significant positive correlation between volatility and firms responsiveness to macro and microlevel shocks consistent with model predictions

price discovery in crude oil futures this study examines price discovery among the two most prominent price benchmarks in the market for crude oil wti sweet crude and brent sweet crude using data on the most active futures contracts measured at the one second frequency we nd that wti maintains a dominant role in price discovery relative to brent with an estimated information share in excess of 80 over a sample from 2007 through 2012 our analysis is robust

deutsche mark dollar volatility intraday activity patterns macroeconomic announcements and longer run dependencies this paper provides a detailed characterization of the volatility in the deutsche mark dollar foreign exchange market using an annual sample of five minute returns the approach captures the intraday activity patterns the macroeconomic announcements and the volatility persistence arch known from daily returns the different features are separately quantified and shown to account for a substantial fraction of return variability both at the intraday and daily level the implications of the results for the interpretation of the fundamental driving forces behind the volatility process is also discussed the efficient market hypothesis contends that financial asset prices provide rational assessments of fundamental values and future payoffs by implication price changes should reflect the arrival and processing of all relevant new information however the proportion of return variability that can be ascribed to public news announcements is low for example cutler poterba and summers 1989 find that even the largest daily price changes in the stock market generally cannot be associated with any significant economic news 1 moreover proxies for the flow of public information e g the number of news items released by reuter s news service berry and hiowe 1994 or dow jones company mitchell and mulherin 1994 explain little of the overall variation thus if private information is ruled out proponents of rational price formation have to assert the existence of important news items

sales and monetary policy this paper analyses the efiect of monetary policy in a model where sales occur in equilibrium some consumers are loyal to a particular brand of a good others are bargain hunters as a result producers flnd it optimal to sell their goods at a normal price through some retailers and at a sale price through others the margin of adjusting the amount sold on sale is potentially very important if producers can adjust the fraction sold on sale with sticky prices and wages money is approximately neutral if we ignore the reasons behind sales but that result changes dramatically when we consider that producers optimally choose to sell some of their goods on sale owing to strategic substitutabilities in the sales decision money has strong procyclical efiects

menu costs and the neutrality of money a model of endogenous price adjustment under money growth is presented firms follow s s pricing policies and price revisions are imperfectly synchronized in the aggregate price stickiness disappears and money is neutral the connection between firm price adjustment and relative price variability in the presence of monetary growth is also investigated the results contrast with those obtained in models with exogenous fixed timing of price adjustment

dynamics of the u s price distribution abstract we use microdata underlying u s consumer producer and import price indices to document how the distribution of price changes evolves over time two striking features characterize pricing across all three datasets 1 frequency of price adjustments is countercyclical 2 frequency of price adjustments is correlated with variance conversely other statistics that have received recent attention like kurtosis do not exhibit uniform patterns across our data sets what implications do our empirical results have for monetary policy using a flexible accounting framework that collapses the high dimensional distribution of price changes into a single measure of aggregate price flexibility we show that flexibility is highly variable and countercyclical

assessing the accuracy of the aggregate law of motion in models with heterogeneous agents this paper shows that the r2 and the standard error have fatal flaws and are inadequate accuracy tests using data from a krusell smith economy i show that approximations for the law of motion of aggregate capital for which the true standard deviation of aggregate capital is up to 14 119 higher than the implied value and which are thus clearly inaccurate can have an r2 as high as 0 9999 0 99 key in generating a more powerful test is that predictions of the aggregate law of motion are not updated with the aggregated simulated individual data

the feasibility costs and environmental implications of large scale biomass energy abstract what are the feasibility costs and environmental implications of large scale bioenegry we investigate this question by developing a detailed representation of bioenergy in a global economy wide model we develop a scenario with a global carbon dioxide price applied to all anthropogenic emissions except those from land use change that rises from 25 per metric ton in 2015 to 99 in 2050 this creates market conditions favorable to biomass energy resulting in global non traditional bioenergy production of 150 exajoules ej in 2050 by comparison in 2010 global energy production was primarily from coal 138 ej oil 171 ej and gas 106 ej with this policy 2050 emissions are 42 less in our base policy case than our reference case although extending the scope of the carbon price to include emissions from land use change would reduce 2050 emissions by 52 relative to the same baseline our results from various policy scenarios show that lignocellulosic lc ethanol may become the major form of bioenergy if its production costs fall by amounts predicted in a recent survey and ethanol blending constraints disappear by 2030 however if its costs remain higher than expected or the ethanol blend wall continues to bind bioelectricity and bioheat may prevail higher lc ethanol costs may also result in the expanded production of first generation biofuels ethanol from sugarcane and corn so that they remain in the fuel mix through 2050 deforestation occurs if emissions from land use change are not priced although the availability of biomass residues and improvements in crop yields and conversion efficiencies mitigate pressure on land markets as regions are linked via international agricultural markets irrespective of the location of bioenergy production natural forest decreases are largest in regions with the lowest barriers to deforestation in 2050 the combination of carbon price and bioenergy production increases food prices by 3 2 5 2 with bioenergy accounting for 1 3 3 5

biomass feedstock contracts role of land quality and yield variability in near term feasibility abstract in the absence of an infrastructure for the harvest storage and purchase of cellulosic biomass contracting is an important mechanism through which biorefineries can ensure adequate feedstock supply we develop an optimization model to assess the economic potential of dedicated energy crops when profit maximizing farmers allocate croplands of varying quality toward biomass in response to multi year contracts we evaluate the economic competitiveness of perennial grasses with traditional commodity crops in a case study of switchgrass production in tennessee assuming short term contracts we consider the importance of payment structure land quality energy crop yield and projected commodity crop returns on a farmer s decision to accept a contract for biomass production we find that a wholesale contract in which the farmer is guaranteed a price per unit biomass is most effective on the highest quality of land while a contract in which the farmer is guaranteed a price per acre is most effective on lower quality land from the biorefinery perspective a wholesale contract is most effective for short term contracts while an acreage contract is most effective for long term contracts breakeven pricing will only secure feedstock from farmers who produce commodity crops with unfavorable price outlooks on lower quality land therefore the contract price must include a premium in order to compete for space in the crop mix the yield profile of energy crops has a significant effect on the terms at which short term contracts will be accepted and land allocated toward feedstock production the extent to which energy crop yields observed in field trials can be maintained at commercial scale also has a substantial effect on the scale at which farmers would be willing to participate in energy crop production

five facts about prices a reevaluation of menu cost models are price decreases 3 the frequency of price increases covaries strongly with inflation whereas the frequency of price decreases and the size of price increases and price decreases do not 4 the frequency of price change is highly seasonal it is highest in the first quarter and then declines 5 we find no evidence of upwardsloping hazard functions of price changes for individual products we show that the first second and third facts are consistent with a benchmark menu cost model whereas the fourth and fifth facts are not

price discount inventories and the distortion of wti benchmark abstract applying a rolling estimation to the hasbrouck information share model this study investigates the changing status of wti benchmark over time results show the ability of wti in reflecting market conditions decreases sharply and wti s efficiency in processing information has been surpassed by brent s since the second half of 2004 in the short run the wti distortion is related to its price discount problem but the distortion cannot be indicated by contangos in the long run wti s price discount problem coexists with a positive forward curve and both have harmed the price discovery role of wti the rising inventories in cushing significantly deteriorate wti s ability in serving as a world benchmark

income and wealth heterogeneity in the macroeconomy how do movements in the distribution of income and wealth affect the macroeconomy we analyze this question using a calibrated version of the stochastic growth model with partially uninsurable idiosyncratic risk and movements in aggregate productivity our main finding is that in the stationary stochastic equilibrium the behavior of the macroeconomic aggregates can be almost perfectly described using only the mean of the wealth distribution this result is robust to substantial changes in both parameter values and model specification our benchmark model whose only difference from the representative agent framework is the existence of uninsurable idiosyncratic risk displays far less cross sectional dispersion and skewness in wealth than u s data however an extension that relies on a small amount of heterogeneity in thrift does succeed in replicating the key features of the wealth data furthermore this extension features aggregate time series that depart significantly from permanent income behavior

price stickiness in ss models new interpretations of old results abstract what is the relation between infrequent price adjustment and the dynamic response of the aggregate price level to monetary shocks the answer to this question ranges from a one to one link calvo g 1983 prices in a utility maximizing framework journal of monetary economics 12 383 398 to no connection whatsoever caplin a spulber d 1987 menu costs and the neutrality of money quarterly journal of economics 102 703 726 the purpose of this paper is to provide a unified framework to understand the mechanisms behind this wide range of results in doing so we propose new interpretations of key results in this area which in turn suggest the kind of ss model that is likely to generate substantial price rigidity among these new interpretations we revisit caplin and spulber s monetary neutrality result we show that when price stickiness is measured in terms of the impulse response function this result is not a consequence of aggregation as is often assumed but is due instead to the absence of price stickiness at the microeconomic level we also show that the selection effect according to which units that adjust their prices are those that benefit the most is neither necessary nor sufficient to account for the higher aggregate flexibility of ss type models compared to calvo models instead the key concept is the contribution of the extensive margin of adjustment to the aggregate price response the aggregate price level is more flexible than suggested by the microeconomic frequency of adjustment if and only if this term is positive

state dependent or time dependent pricing does it matter for recent u s inflation in the 1988 2004 micro data collected by the u s bureau of labor statistics for the cpi price changes are frequent every 4 7 months depending on the treatment of sale prices and large in absolute value on the order of 10 the size and timing of price changes varies considerably for a given item but the size and probability of a price change are unrelated to the time since the last price change movements in aggregate inflation reflect movements in the size of price changes rather than the fraction of items changing price due to offsetting movements in the fraction of price increases and decreases neither leading time dependent models taylor or calvo nor 1 st generation state dependent models match all of these facts some 2 nd generation state dependent models however appear broadly consistent with the empirical patterns

a dynamic economy with costly price adjustments this paper studies a general equilibrium model of a dynamic economy with menu costs each firm s productivity is exposed to idiosyncratic and aggregate productivity shocks around a trend and the money supply to monetary shocks around a trend all consumption pricing and production decisions are based on optimizing behavior there exists a staggered markov perfect equilibrium with prices determined by a two sided s s markup strategy the paper analyzes the optimal markup strategy and investigates the dynamics of the price index and the aggregate output the welfare consequences of the uncertain aggregate productivity and money supply are also examined

impact of energy prices and cellulosic biomass supply on agriculture energy and the environment an integrated modeling approach abstract the accelerated growth in biofuel markets has both created and reinforced linkages between agriculture and energy the evolution of biofuel markets over the next 10 20 years and the implications for energy agriculture and the environment are uncertain building on an integrated agriculture energy modeling framework this study analyzes a baseline and three alternative scenarios two scenarios based on energy prices crude oil and natural gas and one based on assumptions regarding cellulosic biomass availability by examining the impact of scenarios driven by a changes in the energy sector and b changes in the agricultural sector we can compare the differential effects on biofuels markets commodity prices and quantities in each sector and co 2 emissions scenario comparisons show biofuel markets affected more by crude oil prices than natural gas prices however higher natural gas prices shift the biofuel production mix away from corn grain based to more cellulosic ethanol via multiple mechanisms alternatively the scenario with no cellulosic feedstock lowers total ethanol production and raises ethanol and corn prices in terms of environmental impacts higher ethanol levels driven by higher oil prices lead to lower co 2 emissions in comparison the no cellulosic scenario results in the highest co 2 trajectory relative to the baseline

do higher prices for new goods reflect quality growth or inflation much of consumer price index cpi inflation for consumer durables reflects shifts to newer product models that display higher prices not price increases for a given set of goods i examine how these higher prices for new models should be divided between quality growth and price inflation based on a whether consumer purchases shift toward or away from the new models and b whether new model price increases generate higher relative prices that persist through the model cycle i conclude that two thirds of the price increases with new models should be treated as quality growth this implies that cpi inflation for durables has been overstated by almost 2 percentage points per year with quality growth understated by the same magnitude

reference prices costs and nominal rigidities we assess the importance of nominal rigidities using a new weekly scanner dataset we find that nominal rigidities take the form of inertia in reference prices and costst defined as the most common prices and costs within a given quarter reference prices are particularly inertial and have an average duration of roughly one year even though weekly prices change roughly once every two weeks we document the relation between prices and costs and find sharp evidence of state dependence in prices we use a simple model to argue that reference prices and costs are useful statistics for macroeconomic

monetary non neutrality in a multisector menu cost model empirical evidence suggests that as much as one third of the u s business cycle is due to nominal shocks we calibrate a multisector menu cost model using new evidence on the cross sectional distribution of the frequency and size of price changes in the u s economy we augment the model to incorporate intermediate inputs we show that the introduction of heterogeneity in the frequency of price change triples the degree of monetary non neutrality generated by the model we furthermore show that the introduction of intermediate inputs raises the degree of monetary non neutrality by another factor of three without adversely affecting the model s ability to match the large average size of price changes a single sector model with a frequency of price change equal to the median rather than the mean generates monetary non neutrality similar to that in our multisector model our multisector model with intermediate inputs generates variation in real output in response to calibrated aggregate nominal shocks that can account for roughly 23 of the u s business cycle

investigating nonneutrality in a state dependent pricing model with firm level productivity shocks in a model with fixed cost of price adjustment and idiosyncratic shocks two parameterizations match a large set of microeconomic facts yet display different degrees of nonneutrality although there is substantial nonneutrality in both cases the model does not behave like a time dependent model as changes in the distribution of firms account for roughly a third of the short run response of the price level to a monetary shock we use the model to examine how aggregating firm behavior can generate flat hazards we also find that a recently developed steady state statistic is an imperfect guide to characterizing nonneutrality

sticky prices and costly credit we develop a theory of money and credit as competing payment instruments then put it to work in applications agents use cash and credit because the former latter is subject to the inflation tax transaction costs frictions that make the choice of payment method interesting also imply equilibrium price dispersion we derive closed form solutions for money demand and show how to simultaneously account for the price change facts cash credit shares in micro data and money interest correlations in macro data the effects of inflation on welfare price dispersion and markups are discussed as are nonstationary equilibria with dynamics in the price distribution

state dependent pricing and the general equilibrium dynamics of money and output economists have long suggested that nominal product prices are changed infrequently because of fixed costs in such a setting optimal price adjustment should depend on the state of the economy yet while widely discussed statedependent pricing has proved difficult to incorporate into macroeconomic models this paper develops a new tractable theoretical state dependent pricing framework we use it to study how optimal pricing depends on the persistence of monetary shocks the elasticities of labor supply and goods demand and the interest sensitivity of money demand

uncertainty shocks and unemployment dynamics in u s recessions abstract what are the effects of uncertainty shocks on unemployment dynamics we answer this question by estimating non linear smooth transition vars with post wwii u s data the relevance of uncertainty shocks is found to be much larger than that predicted by standard linear vars in terms of i magnitude of the reaction of the unemployment rate to such shocks and ii contribution to the variance of the prediction errors of unemployment at business cycle frequencies the ability of different classes of dsge models to replicate our results is discussed

land requirements feedstock haul distance and expected profit response to land use restrictions for switchgrass production abstract energy crop production has been proposed for land of poor quality to avoid competition with food production and negative indirect land use consequences the objective of this study was to determine the land area requirements biomass transportation distance and expected profit consequences of restricting switchgrass biomass production for use as biofuel feedstock to marginal land relative to unrestricted land use the usa soils capability classification system was used to differentiate between high quality land and land of marginal quality fifty years of historical weather data were used in combination with a biophysical simulation model to estimate switchgrass biomass yield distributions for land of different quality for counties in the case study region a mathematical programming model was designed and solved to determine the economic consequences for the levels of biofuel price considered 0 50 0 75 and 1 00 l and a 262 5 m l year biorefinery modeled restricting land use to marginally productive capability class iv soils increases the quantity of land optimally leased by 42 to 52 increases biomass trucking total transportation distance by 115 to 116 and reduces the expected net returns by 11 to 15 m year compared to when land use is unrestricted in the absence of government restrictions for profit companies are not likely to limit energy crop production to land of marginal quality

the dynamics of crude oil price differentials abstract crude oil price differentials are modelled as a two regime threshold autoregressive tar process using the method proposed by caner and hansen caner m hansen b e threshold autoregression with a unit root econometrica 2001 69 1555 1596 while standard unit root tests suggest that the prices of crude oil of different varieties move closely together such that their price differential is stationary the tar results indicate strong evidence of threshold effects in the adjustment process to the long run equilibrium these findings suggest that crude oil prices are linked and thus at the very general level the oil market is one great pool adelman m a international oil agreements the energy journal 1984 5 1 9 however differences in the dynamics of adjustment suggest that within this one pool oil markets are not necessarily integrated in every time period and hence the dynamics of crude oil price differentials may not follow a stationary process at all times although the development of a liquid futures market around the crude oil benchmarks has helped make some distant markets more unified arbitrage is not costless or risk free and temporary breakdowns in the benchmarks can lead to decoupling of crude oil prices

inflation dynamics and time varying volatility new evidence and an ss interpretation is monetary policy less effective at increasing real output during periods of high volatility than during normal times in this article i argue that greater volatility leads to an increase in aggregate price flexibility so that nominal stimulus mostly generates inflation rather than output growth to do this i construct price setting models with volatility shocks and show these models match new facts in cpi micro data that standard price setting models miss i then show that these models imply that output responds less to nominal stimulus during times of high volatility furthermore because volatility is countercyclical this implies that nominal stimulus has smaller real effects during downturns for example the estimated output response to additional nominal stimulus in september 1995 a time of low volatility is 55 larger than the response in october 2001 a time of high volatility jel codes e10 e30 e31 e50 d8 copyright 2014 oxford university press