natural resources curse or blessing are natural resources a curse or a blessing the empirical evidence suggests that either outcome is possible this paper surveys a variety of hypotheses and supporting evidence for why some countries benefit and others lose from the presence of natural resources these include that a resource bonanza induces appreciation of the real exchange rate deindustrialization and bad growth prospects and that these adverse effects are more severe in volatile countries with bad institutions and lack of rule of law corruption presidential democracies and underdeveloped financial systems another hypothesis is that a resource boom reinforces rent grabbing and civil conflict especially if institutions are bad induces corruption especially in nondemocratic countries and keeps in place bad policies finally resource rich developing economies seem unable to successfully convert their depleting exhaustible resources into other productive assets the survey also offers some welfare based fiscal rules for harnessing resource windfalls in developed and developing economies

answering the skeptics yes standard volatility models do provide accurate forecasts a voluminous literature has emerged for modeling the temporal dependencies in financial market volatility using arch and stochastic volatility models while most of these studies have documented highly significant in sample parameter estimates and pronounced intertemporal volatility persistence traditional ex post forecast evaluation criteria suggest that the models provide seemingly poor volatility forecasts contrary to this contention we show that volatility models produce strikingly accurate interdaily forecasts for the latent volatility factor that would be of interest in most financial applications new methods for improved ex post interdaily volatility measurements based on high frequency intradaily data are also discussed

uncertainty risk and the financial crisis of 2008 the distinction between uncertainty and risk originally drawn by frank knight and john maynard keynes in the 1920s remains fundamentally important today in the presence of uncertainty market actors and economic policy makers substitute other methods of decision making for rational calculation specifically actors decisions are rooted in social conventions drawing from innovations in financial markets and deliberations among top american monetary authorities in the years before the 2008 crisis we show how economic actors and policy makers live in worlds of risk and uncertainty in that world social conventions deserve much greater attention than conventional ipe analyses accords them such conventions must be part of our toolkit as we seek to understand the preferences and strategies of economic and political actors

developing a stress testing framework based on market risk models the basel 2 accord requires regulatory capital to cover stress tests yet no coherent and objective framework for stress testing portfolios exists we propose a new methodology for stress testing in the context of market risk models that can incorporate both volatility clustering and heavy tails empirical results compare the performance of eight risk models with four possible conditional and unconditional return distributions over different rolling estimation periods when applied to major currency pairs using daily data spanning more than 20 years we find that stress test results should have little impact on current levels of foreign exchange regulatory capital

nonlinearly weighted convex risk measure and its application abstract we propose a new class of risk measures which satisfy convexity and monotonicity two well accepted axioms a reasonable and realistic risk measure should satisfy through a nonlinear weight function the new measure can flexibly reflect the investor s degree of risk aversion and can control the fat tail phenomenon of the loss distribution a realistic portfolio selection model with typical market frictions taken into account is established based on the new measure real data from the chinese stock markets and american stock markets are used for empirical comparison of the new risk measure with the expected shortfall risk measure the in sample and out of sample empirical results show that the new risk measure and the corresponding portfolio selection model can not only reflect the investor s risk averse attitude and the impact of different trading constraints but can find robust optimal portfolios which are superior to the corresponding optimal portfolios obtained under the expected shortfall risk measure

estimating financial risk measures for options abstract this paper proposes a simulation lattice procedure to estimate financial risk measures for option positions the framework proposed can be applied to many different kinds of options including exotic and vanilla options it can take account of early exercise features heavy tails in underlying processes estimate different risk measures including var expected shortfall and spectral risk measures and in a limited way it can be generalized to accommodate multiple factors it avoids many of the limitations of existing approaches and in particular avoids the problems associated approaches based on delta gamma and similar approximations it also generates some interesting results about the risk measures of some illustrative options positions

second best foreign exchange policy in the presence of domestic price controls and export subsidies poland like many developing countries has required its exports to surrender a share of their foreign exchange earnings to the government at an overvalued exchange rate during the late 1980s it progressively increased the share which exporters were allowed to retain the retention ratio but other distortions to the trade regime remained a model developed here estimates the effects of these policies on welfare under different foreign exchange elasticities export and import subsidies official exchange rates and policies on exporter retention of foreign exchange earnings the retention ratios in effect in early 1989 were equivalent to a 51 percent tax on exports or an import tariff of 130 percent as economic theory would suggest maximum social benefit would derive from removal of the full range of distortions full retention of foreign exchange by exporters in the absence of other distortions would provide social benefits equivalent to 8 percent of gross domestic product but the net effect of the other policies together is a bias toward tradables so that a policy of somewhat less than full retention of foreign exchange is optimal in this second best world

evaluating interval forecasts a complete theory for evaluating interval forecasts has not been worked out to date most of the literature implicitly assumes homoskedastic errors even when this is clearly violated and proceed by merely testing for correct unconditional coverage consequently i set out to build a consistent framework for conditional interval forecast evaluation which is crucial when higher order moment dynamics are present the new methodology is demonstrated in an application to the exchange rate forecasting procedures advocated in risk management

liquidity adjusted intraday value at risk modeling and risk management an application to data from deutsche borse abstract this paper develops a high frequency risk measure the liquidity adjusted intraday value at risk livar our objective is to explicitly consider the endogenous liquidity dimension associated with order size by reconstructing the open limit order book of deutsche borse changes in the tick by tick ex ante frictionless return and actual return are modeled jointly the risk related to the ex ante liquidity premium is then quantified our model can be used to identify the impact of ex ante liquidity risk on total risk and to provide an estimation of the var for the actual return at a point in time in our sample liquidity risk can account for up to 32 of total risk depending on order size

forecasting portfolio value at risk with nonparametric lower tail dependence estimates abstract we propose to forecast the value at risk of bivariate portfolios using copulas which are calibrated on the basis of nonparametric sample estimates of the coefficient of lower tail dependence we compare our proposed method to a conventional copula garch model where the parameter of a clayton copula is estimated via canonical maximum likelihood the superiority of our proposed model is exemplified by analyzing a data sample of nine different bivariate and one nine dimensional financial portfolio a comparison of the out of sample forecasting accuracy of both models confirms that our model yields economically significantly better value at risk forecasts than the competing parametric calibration strategy

mean var portfolio optimization a nonparametric approach portfolio optimization involves the optimal assignment of limited capital to different available financial assets to achieve a reasonable trade off between profit and risk we consider an alternative markowitz s mean variance model in which the variance is replaced with an industry standard risk measure value at risk var in order to better assess market risk exposure associated with financial and commodity asset price fluctuations realistic portfolio optimization in the mean var framework is a challenging problem since optimizing var leads to a non convex np hard problem which is computationally intractable in this work an efficient learning guided hybrid multi objective evolutionary algorithm mode gl is proposed to solve mean var portfolio optimization problems with real world constraints such as cardinality quantity pre assignment round lot and class constraints a learning guided solution generation strategy is incorporated into the multi objective optimization process to promote efficient convergence by guiding the evolutionary search towards promising regions of the search space the proposed algorithm is compared against the non dominated sorting genetic algorithm nsga ii and the strength pareto evolutionary algorithm spea2 experimental results using historical daily financial market data from s p 100 and s p 500 indices are presented experimental results shows that mode gl outperforms two existing techniques for this important class of portfolio investment problems in terms of solution quality and computational time the results highlight that the proposed algorithm is able to solve the complex portfolio optimization without simplifications while obtaining good solutions in reasonable time and has significant potential for use in practice

tail risk of electricity futures abstract this paper compares the in sample and out of sample performance of several models for computing the tail risk of one month and one year electricity futures contracts traded in the nordpool french german and spanish markets in 2008 2017 as measures of tail risk we use the one day ahead value at risk var and the expected shortfall es with var the ar 1 garch 1 1 model with student t distribution is the best performing specification with 88 cases in which the fisher test accepts the model with a success rate of 94 in the left tail and of 81 in the right tail the model passes the test of model adequacy in the 100 of the cases in the nordpool and german markets but only in the 88 and 63 of the cases in the spanish and french markets with es this model passes the test of model adequacy in 100 of cases in all markets historical simulation and quantile regression based approaches misestimate tail risks the right hand tail of the returns is more difficult to model than the left hand tail and therefore financial regulators and the administrators of futures markets should take these results into account when setting additional regulatory capital requirements and margin account regulations to short positions

bank capital regulation of trading portfolios an assessment of the basel framework in setting minimum capital requirements for trading portfolios the basel committee on banking supervision 1996 2011a 2013 initially used value at risk var then both var and stressed var svar and most recently stressed conditional var scvar accordingly we examine the use of scvar to measure risk and set these requirements assuming elliptically distributed asset returns we show that portfolios on the mean scvar frontier generally lie away from the mean variance m v frontier in a plausible numerical example we find that such portfolios tend to have considerably higher ratios of risk measured by e g standard deviation to minimum capital requirement than those of portfolios on the m v frontier also we find that requirements based on scvar are smaller than those based on both var and svar but exceed those based on just var finally we find that requirements based on scvar are less procyclical than those based on either var or both var and svar overall our paper suggests that the use of scvar to measure risk and set requirements is not a panacea

do banks overstate their value at risk abstract this paper is the first empirical study of banks risk management systems based on non anonymous daily value at risk var and profit and loss data using actual data from the six largest canadian commercial banks we uncover evidence that banks exhibit a systematic excess of conservatism in their var estimates the data used in this paper have been extracted from the banks annual reports using an innovative matlab based data extraction method out of the 7354 trading days analyzed in this study there are only two exceptions i e days when the actual loss exceeds the disclosed var whereas the expected number of exceptions with a 99 var is 74 for each sample bank we extract from historical vars a risk overstatement coefficient ranging between 19 and 79 we attribute var overstatement to several factors including extreme cautiousness and underestimation of diversification effects when aggregating vars across business lines and or risk categories we also discuss the economic and social cost of reporting inflated vars

the level and quality of value at risk disclosure by commercial banks in this paper we study both the level of value at risk var disclosure and the accuracy of the disclosed var figures for a sample of us and international commercial banks to measure the level of var disclosures we develop a var disclosure index that captures many different facets of market risk disclosure using panel data over the period 1996 2005 we find an overall upward trend in the quantity of information released to the public we also find that historical simulation is by far the most popular var method we assess the accuracy of var figures by studying the number of var exceedances and whether actual daily vars contain information about the volatility of subsequent trading revenues unlike the level of var disclosure the quality of var disclosure shows no sign of improvement over time we find that var computed using historical simulation contains very little information about future volatility

conditional heteroscedasticity in time series of stock returns evidence and forecasts this article presents new evidence about the time series behavior of stock prices daily return series exhibit significant levels of second order dependence and they cannot be modeled as linear white noise processes a reasonable return generating process is empirically shown to be a first order autoregressive process with conditionally heteroskedastic innovations in particular generalized autoregressive conditional heteroskedastic garch 1 1 processes fit to data very satisfactorily various out of sample forecasts of monthly return variances are generated and compared statistically forecasts based on the garch model are found to be superior copyright 1989 by the university of chicago

a note on the importance of overnight information in risk management models this paper examines the economic value of overnight information to users of risk management models in addition to the information revealed by overseas markets that trade during the domestic overnight period this paper exploits information generated via recent innovations in the structure of financial markets in particular certain securities and associated derivative products can now be traded at any time over a 24 h period as such it is now possible to make use of information generated by trading in almost identical securities during the overnight period of the securities that are available over such time periods s p 500 related products are by far the most actively traded and are therefore the subject of this paper using a variety of conditional volatility models that allow time dependent information flow within and across three different s p 500 markets the results show that overnight information flow has a significant impact on the conditional volatility of daytime traded s p 500 securities moreover time consistent forecasts from models that incorporate overnight information are shown to have economic value to risk managers in particular value at risk var models based on these conditional volatility models are shown to be more accurate than var models that ignore overnight information

bank regulation and international financial stability a case against the 2006 basel framework for controlling tail risk in trading books abstract in attempting to promote international financial stability the basel committee on banking supervision 2006 provided a framework that sought to control the amount of tail risk that large banks around the world would take in their trading books relative to their corresponding minimum capital requirements however many of these banks suffered significant trading losses during the recent financial crisis our paper examines whether the basel framework allowed banks to take substantive tail risk in their trading books without a capital requirement penalty we find that it allowed banks to do so and that its minimum capital requirements can be notably procyclical hence focusing on the way the basel framework sought to control the amount of tail risk in trading books relative to their corresponding minimum capital requirements our paper supports the view that it was not properly designed to promote financial stability we also discuss alternative regulatory frameworks that would potentially be more effective than the basel framework in preventing banks from taking substantive tail risk in their trading books without a capital requirement penalty

diversification and value at risk a pervasive and puzzling feature of banks value at risk var is its abnormally high level which leads to excessive regulatory capital a possible explanation for the tendency of commercial banks to overstate their var is that they incompletely account for the diversification effect among broad risk categories e g equity interest rate commodity credit spread and foreign exchange by underestimating the diversification effect bank s proprietary var models produce overly prudent market risk assessments in this paper we examine empirically the validity of this hypothesis using actual var data from major us commercial banks in contrast to the var diversification hypothesis we find that us banks show no sign of systematic underestimation of the diversification effect in particular diversification effects used by banks is very close to and quite often larger than our empirical diversification estimates a direct implication of this finding is that individual vars for each broad risk category just like aggregate vars are biased risk assessments

wealth and sustainability for economists in 1974 it was a live question whether the exhaustion of natural resources such as oil would necessarily lead to the decline of economic activity solow showed that constant levels of consumption could be sustained in the face of exhaustibility if there is sufficient substitutability between produced and natural factors of production hartwick then proved that underpinning this result is a saving rule set investment in produced capital equal to the value of resource depletion at each point in time a large literature has shown that a comprehensive measure of the change in real wealth net saving plays a central role in determining whether current well being can be sustained in particular current declines in real wealth signal that future well being will also decline a result that has been confirmed empirically using data for developing countries changes in wealth and sustainability are therefore joined at the hip the current composition of wealth serves to define the policy challenges that countries face in achieving sustainable development if substitution possibilities are limited between natural and other factors of production as one might expect then technical progress is a necessary complement to policies for sustainability

savings growth and the path of utility we derive an expression relating the change in instantaneous utility to the growth of net genuine saving in an economy with multiple stocks and externalities that maxi mizes welfare in the utilitarian sense this result is then shown to hold for decentralized competitive efficient economies as well to yield an extension of the hartwick rule instan taneous utility is non declining along a development path if genuine saving is decreasing by way of example the rule is applied as a constant genuine saving rate rule in a simple dasgupta heal solow stiglitzeconomy the rule yields a path with unbounded consump tion and higher wealth than on the standard hartwick constant consumption path jel classification q01 q56 o13

intertemporal equity and efficient allocation of resources abstract competitive paths which are efficient are shown to satisfy a terminal cost minimization condition thereby providing a continuous time counterpart to the discrete time result due to malinvaud using this result competitive paths which are equitable and efficient are shown to satisfy hartwick s investment rule which states that the value of net investment is zero at each date our result indicates that hartwick s rule can help to signal inefficiency of competitive equitable paths journal of economic literature classification numbers c61 d90 o41

from value at risk to stress testing the extreme value approach this article presents an application of extreme value theory to compute the value at risk of a market position in statistics extremes of a random process refer to the lowest observation the minimum and to the highest observation the maximum over a given time period extreme value theory gives some interesting results about the distribution of extreme returns in particular the limiting distribution of extreme returns observed over a long time period is largely independent of the distribution of returns itself in financial markets extreme price movements correspond to market corrections during ordinary periods and also to stock market crashes bond market collapses or foreign exchange crises during extraordinary periods an approach based on extreme values to compute the var thus covers market conditions ranging from the usual environment considered by the existing var methods to the financial crises which are the focus of stress testing univariate extreme value theory is used to compute the var of a fully aggregated position while multivariate extreme value theory is used to compute the var of a position decomposed on risk factors 2000 elsevier science b v all rights reserved

the hartwick rule myths and facts we shed light on the hartwick rule for capital accumulation and resource depletion by providing semantic clarifications and investigating the implications and relevance of this rule we extend earlier results by establishing that the hartwick rule does not indicate sustainability and does not require substitutability between man made and naturalcapital we use a new class of simple counterexamples i to obtain the novel finding that a negative value of net investments need not entail that utility is unsustainable and ii to point out deficiencies in the literature

an environmental economic measure of sustainable development abstract a central issue in the study of sustainable development is the interplay of growth and sacrifice in a dynamic economy this paper investigates the relationship among current consumption sacrifice and sustainability improvement in a general context and in two canonical stylized economies we argue that the maximin value of utility measures what is sustainable and provides the limit to growth maximin value is interpreted as a dynamic environmental economic carrying capacity and current utility as an environmental economic footprint the time derivative of maximin value is interpreted as net investment in sustainability improvement it is called durable savings to distinguish it from genuine savings usually computed with discounted utilitarian prices

characterizing sustainability the converse of hartwick s rule this note offers a general proof of the converse of hartwick s rule namely that in an economy with stationary instantaneous preferences and a stationary technology an efficient constant utility path is characterized by the value of net investments being zero at each point in time in a one consumption economy with two stocks a stock of a natural resource and a stock of man made capital this means that if consumption remains constant at the maximum sustainable level then the accumulation of man made capital always exactly compensates in value for the depletion of the natural resource

volatility forecasting without data snooping abstract data snooping arises when the properties of a data series influence the researcher s choice of model specification when data has been snooped tests undertaken using the same series are likely to be misleading this study seeks to predict equity market volatility using daily data on u k stock market returns over the period 1955 1989 we find that even apparently innocuous forms of data snooping significantly enhance reported forecast quality and that relatively sophisticated forecasting methods operated without data snooping often perform worse than naive benchmarks for predicting stock market volatility we therefore recommend two alternative models both of which are extremely simple

assessing sustainability a comprehensive wealth accounting prospect an application to mozambique we estimate the wealth of mozambique in 2000 and 2005 in order to assess the sustainability of its development path our methodology builds on arrow et al 2010 we show that mozambican wealth increases through human and physical capital accumulation while the pressure on natural capital remains low the growth of total factor productivity enhances the outcome of the different capital assets but population growth has a strong downward effect on wealth per capita results suggest that mozambican development was sustainable between 2000 and 2005 but these remain ambiguous and are highly sensitive to data and assumptions used

exact consumer s surplus and deadweight loss consumer s surplus is a widely used tool in applied welfare economics both economic theorists and cost benefit analysis often use consumer s surplus despite its somewhat dubious reputation the basic idea is to evaluate the value to a consumer or his willingness to pay for a change in price of a good from say pricep to pricep because price changes affect consumer welfare an evaluation of this effect is often a key input to public policy decisions yet consumer s surplus is probably the most controversial of widely used economic concepts both paul samuelson and ian little conclude that the economics profession would be better off without it it is my feeling of the situation that substantial agreement exists on the correct quantities to be measured the amount the consumer would pay or would need to be paid to be just as well off after the price change as he was before the price change the quantities correspond to john hicks compensating variation measures an alternative measure which takes ex post price change utility as the basis of comparison is hicks equivalent variation the controversy arises in the measurement of these quantities the usual measurement procedure is to use the area to the left of the marshallian market demand curve between two price levels jules dupuit originated this measure of welfare change and alfred marshall and hicks derived appropriate conditions for its use the primary condition for the area to the left of the demand curve to correspond to the compensating variation is to have constant marginal utility of income marshall gave this condition and if it holds the same quantity will be derived as the area to the left of the compensated hicksian demand curve this area to the left of the compensated demand curve is exactly what the compensating variation and equivalent variation measure thus the constant marginal utility of income is a sufficient condition for marshallian consumer s surplus to be equal to hicks consumer s surplus in this case arnold harberger s plea to use the welfare triangle as one half times the product of the price change times the quantity change to measure deadweight loss corresponds to the correct theoretical amount of welfare change in a recent paper robert willig derives bounds for the percentage difference between the correct measure of either the compensating or equivalent variation and the marshallian measure derived form the market demand curve his bounds which depend on the income elasticity of demand for the single good in the region of price change being considered as well as the proportion of the consumer s income spent on the good demonstrate that the marshallian consumer s surplus is often a good approximation to hicks consumer s surplus the fact that the proportion of the consumer s income spent matters as well as the income elasticity was first pointed out by harold hotelling willig contends that the approximation error will be less than the errors involved in estimating the demand curve thus he hopes to remove the need for apology that applied economists often need to give to theorists who remark on the inappropriateness of using marshallian consumer s surplus to measure welfare change however in this paper i show that for the case primarily considered by willig of a single price change which is also the situation in which consumer s surplus is often used in applied work no approximation is necessary professor of economics massachusetts institute of technology and research associate national bureau of economic research i would like to thank peter diamond erwin diewert daniel mcfadden robert merton robert solow hal varian joel yellin and the referees for help and comments research support from the national science foundation is acknowledged the reason that we still have two rather than one of samuelson s six measures of consumer s surplus arises from an index number problem of the correct basis for the welfare comparison i will give both measures but plan to concentrate on the compensating variation

integrated models of capital adequacy why banks are undercapitalised with the majority of large uk and many us banks collapsing or being forced to raise capital over the 2007 9 period blaming bankers may be satisfying but is patently insucient basel ii and federal oversight frameworks also deserve criticism we propose that the current methodological void at the heart of basel ii pillar 2 is filled with the recommendation that banks develop fully integrated models for economic capital that relate asset values to fundamental drivers of risk in the economy to capture systematic eects and inter asset dependencies in a way that crude correlation assumptions do not we implement a fully integrated risk analysis based on the balance sheet of a representative eurobank using an economic scenario generation model calibrated to conditions at the end of 2007 our results suggest that the more modular correlation based approaches to economic capital that currently dominate practice will have led to an undercapitalisation of banks a

the relation between implied and realized volatility abstract previous research finds the volatility implied by s p 100 index option prices to be a biased and inefficient forecast of future volatility and to contain little or no incremental information beyond that in past realized volatility in contrast we find that implied volatility outperforms past volatility in forecasting future volatility and even subsumes the information content of past volatility in some of our specifications our results differ from previous studies because we use longer time series and nonoverlapping data a regime shift around the october 1987 crash explains why implied volatility is more biased in previous work

genuine savings and sustainability genuine savings gs has emerged as the leading economic indicator of sustainable economic development at the country level it derives from the literatures on weak sustainability wealth accounting and national income accounting we discuss the theoretical underpinnings of gs focusing on the relationship between changes in a nation s extended capital stock and the future path of consumption the indicator has entered widespread use propelled by the world bank s publications despite its varying performance as a predictor for future consumption notwithstanding the extensive body of literature reviewed promising future research avenues are identified

sustainable development the hartwick rule and optimal growth defining sustainable development as non declining utility the consistency of this concept with the hartwick rule and optimal growth is explored when resources are exhaustible a simple proof that a generalized hartwick rule is necessary and sufficient for constant consumption is derived the existence of a maximal constant consumption path is shown to depend critically on the elasticity of substitution if this is less than 1 consumption declines if it is greater than 1 then consumption is not maximal if it is equal to 1 the cobb douglas case then existence is proved consumption can increase along an optimal path if the pure rate of time preference is 0 if it is non zero then consumption declines

hartwick s rule and maximin paths when the exhaustible resource has an amenity value abstract this paper studies the maximin paths of the canonical dasgupta heal solow model when the stock of natural capital is a direct argument of well being besides consumption hartwick s rule then appears as an efficient tool to characterize solutions in a variety of settings we start with the case without technical progress we obtain an explicit solution of the maximin problem in the case where production and utility are cobb douglas when the utility function is ces with a low elasticity of substitution between consumption and natural capital we show that it is optimal to preserve forever a critical level of natural capital determined endogeneously we then study how technical progress affects the optimal maximin paths in the cobb douglas utility case on the long run path of the economy capital production and consumption grow at a common constant rate while the resource stock decreases at a constant rate and is therefore completely depleted in the very long run a higher amenity value of the resource stock leads to faster economic growth but to a lower long run rate of depletion we then develop a complete analysis of the dynamics of the maximin problem when the sole source of well being is consumption and provide a numerical resolution of the model with resource amenity the economy consumes produces and invests less in the short run if the resource has an amenity value than if it does not whereas it is the contrary in the medium and long runs however and without surprise the resource stock remains for ever higher with resource amenity than without

an evaluation of bank measures for market risk before during and after the financial crisis abstract we study the performance and behavior of value at risk measures used by a number of large u s banks before during and after the financial crisis alternative benchmark var measures including garch based measures are estimated directly from the banks trading revenues to explain the bank var performance results while overly conservative in both the pre crisis and post crisis periods bank var exceedances were excessive and clustered in the crisis period this contrasted with mostly unbiased benchmark hs and garch vars in the pre crisis and post crisis periods and vastly superior garch based var performance in the crisis period with lower exceedance rates and no exceedance clustering our results document the bank vars very slow adjustment to changing market conditions and their systematic bias in all studied periods our results indicate that bank vars could be improved by the use of models with time varying volatility and built on banks knowledge of their current positions

extreme risk modeling an evt pair copulas approach for financial stress tests abstract this paper presents a semi parametric copula garch risk model for financial return series with a stress testing perspective the marginal distributions of the returns are specified using the extreme value theory evt putting a specific emphasis on extreme returns the joint distribution is then built up using the pair copulas theorem based on the marginal distributions and the pair dependence structures the model performance is assessed for three sets of assets namely equity indices exchange rates and commodity prices the empirical results support a better static and dynamic properties of the presented model compared to most common specifications used in practice the proposed model and the alternative specifications are then carried out to perform stress testing exercises on hypothetical portfolios where financial returns are considered as risk factors the results show that the use of a wide range of risk models produce significantly different results in terms of the corresponding stress scenario and in the corresponding impact on the portfolios hence considering flexible and consistent specifications as in the proposed model allows ensuring a better credibility of the stress scenario and enhances the usefulness of the stress testing results

constant savings rates and quasi arithmetic population growth under exhaustible resource constraints in the dasgupta heal solow stiglitz dhss model of capital accumulation and resource depletion we show the following equivalence if an efficient path has constant gross and net of population growth savings rates then population growth must be quasi arithmetic and the path is a maximin or a classical utilitarian optimum conversely if a path is optimal according to maximin or classical utilitarianism with constant elasticity of marginal utility under quasi arithmetic population growth then the gross and net of population growth savings rates converge asymptotically to constants

malthus in the light of climate change abstract to reconsider the malthusian predictions of natural limits to economic development the paper develops a multi sector growth model with exhaustible resource extraction investments in physical and knowledge capital climate change and endogenous fertility economic growth is driven by endogenous innovations which increase in the availability and productivity of research labour poor substitution of natural resources triggers sectoral change climate change is the result of polluting resource use which is like consumption and investments based on the intertemporal optimization of the households highlighting the importance of bounded resource supply and of rational extraction decisions i show that climate change is independent of population growth in steady state and there is no causal relationship between climate and population during transition to steady state the consumption per capita growth rate rises in the innovation rate and the output elasticities of labour and capital in the different sectors unlike climate policy population policy is not warranted it may be counterproductive because labour is crucial for the research sector

an evaluation of the basle guidelines for backtesting banks internal risk management models the 1996 amendment to the baste capital accord to incorporate market risks constitutes a breakthrough in the determination of capital requirements rather than dictating these requirements through a uniform supervisory approach banks are allowed to use their own internal models for computing the capital required in order to mitigate moral hazard problems and stimulate banks to use adequate internal models the models must be subjected to a backtesting procedure if a model produces too many incorrect predictions increased capital requirements result this paper provides an evaluation of the current internal models approach in conjunction with the proposed backtesting procedure in particular using a stylized representation of the present supervisory framework we investigate whether banks are provided with the right incentives to come up with the correct internal model we find that under the current regulatory framework banks are prone to under reporting their true market risk a much stricter penalty scheme is required in order to align banks incentives with those of the supervisor we check the sensitivity of our results to changes in the length of the planning horizon portfolio risk time preferences risk attitudes and the distribution of financial returns

constant per capita consumption paths with exhaustible resources and decaying produced capital abstract we introduce decay in produced capital and exogenous technical progress to the recent solow model of asheim et al with population growth and observe the possible collapse of the economy given too high a rate of decay enough technical progress can restore sustainable per capita consumption

value at risk for long and short trading positions in this paper we model value at risk var for daily stock index returns using a collection of parametric models of the arch family based on the skewed student distribution we show that models that rely on a symmetric density distribution for the error term underperform with respect to skewed density models when the left and right tails of the distribution of returns must be modelled thus var for traders having both long and short positions is not adequately modelled using usual normal or student distributions we suggest using an aparch model based on the skewed student distribution to fully take into account the fat left and right tails of the returns distribution this allows for an adequate modelling of large returns defined on long and short trading positions the performances of all models are assessed on daily data for the cac40 dax nasdaq nikkei and smi stock indexes we also compute the expected short fall and the average multiple of tail event to risk measure for the new model

intertemporal equity and hartwick s rule in an exhaustible resource model in a standard exhaustible resource model it is known that if along a competitive path investment in the augmentable capital good equals the rents on the exhaustible resource known as hartwick s rule then the path is equitable in the sense that the consumption level is constant over time in this paper we show the converse of this result if a competitive path is equitable then it must satisfy hartwick s rule

forecasting exchange rate volatility abstract exchange rate volatility forecasts are obtained using a fractionally integrated garch model gains in forecast accuracy associated with a fractionally integrated model compared to a garch or igarch model are shown to be substantial in many cases

augmenting the world bank s estimates ireland s genuine savings through boom and bust abstract the world bank computes estimates of genuine savings gs a leading indicator of sustainable development for most countries a well established literature has called for methodological enhancement this paper presents augmented estimates of irish gs throughout a period of unprecedented economic expansion and decline 1990 2016 a time series constructed predominantly from national sources includes the most comprehensive coverage of pollutants in the literature surveyed we apply a novel method to aid the property rights designation assessment required for transboundary pollutant accounting in sharp contrast to the world bank s estimates our findings suggest that a modern developed economy can exhibit signs of unsustainability furthermore extended environmental damages drive these results suggesting expanded country specific gs may diverge considerably from the world bank s estimates we find rapid economic development and rapid declines in environmental damages can occur concurrently and on the transition away from an unsustainable path

a general approach to welfare measurement through national income accounting a framework is developed for analyzing national income accounting using a revealed welfare approach that is sufficiently general to cover both the standard discounted utilitarian and maximin criteria as special cases we show that the basic welfare properties of comprehensive national income accounting previously ascribed only to the discounted utilitarian case extend to this more general framework in particular under a wider range of circumstances it holds that real nnp growth or equivalently a positive value of net investments indicates welfare improvement we illustrate the applicability of our approach in the dasgupta heal solow model of capital accumulation and resource depletion

the pernicious effects of contaminated data in risk management banks hold capital to guard against unexpected surges in losses and long freezes in financial markets the minimum level of capital is set by banking regulators as a function of the banks own estimates of their risk exposures as a result a great challenge for both banks and regulators is to validate internal risk models we show that a large fraction of us and international banks uses contaminated data when testing their models in particular most banks validate their market risk model using profit and loss p l data that include fees and commissions and intraday trading revenues this practice is inconsistent with the definition of the employed market risk measure using both bank data and simulations we find that data contamination has dramatic implications for model validation and can lead to the acceptance of misspecified risk models moreover our estimates suggest that the use of contaminated data can significantly reduce market risk induced regulatory capital

a comparison of the original and revised basel market risk frameworks for regulating bank capital abstract recognizing that many banks suffered trading losses that notably exceeded their minimum capital requirements during the recent crisis the basel committee on banking supervision 2011 revised its regulatory framework for trading portfolios in this paper we compare 1 the relative effectiveness of risk management systems based on the original and revised frameworks in controlling tail risk and 2 the relative adequacy of these frameworks in setting minimum capital requirements our main findings are as follows first both systems allow the selection of portfolios with substantive tail risk but one based on the revised framework tends to be less effective in controlling tail risk second the minimum capital requirements set by the revised framework are much less likely to be wiped out by trading losses than those set by the original framework hence on balance the revised framework improves upon the original framework we also suggest further improvements for consideration by bank regulators

improving the parkinson method of estimating security price volatilities the author proposes a new method for estimating the volatility parameters of security prices which is an improvement of the estimation method by m parkinson 1980 the author assumes that the security prices follow the geometric brownian motion however contrary to the setting of parkinson the geometric brownian motion may have nonzero drift terms the author shows that the efficiency of his estimator is about 10 in comparison with the standard sample variance estimator since the efficiency of the estimator by parkinson is about 4 91 his estimation method may considerably improve the estimation methods already known in financial economics copyright 1992 by university of chicago press

a distributional argument for supply side climate policies this paper presents a distributional argument for the use of supply side climate policies whereby carbon emissions are controlled through i depletion quotas or ii permanent confiscation of a fraction of the in situ carbon stocks the modeling considers intertemporal competitive equilibria in the cobb douglas version of the dasgupta heal solow stiglitz model of capital accumulation and costless resource extraction it is shown how policies i and ii preserve the functional distribution of income between capital owners and resource owners compared to the case where no climate policy is needed while suggested demand side policies do not such observations are of interest as avoiding functional redistribution may facilitate climate change negotiations the paper discusses policy implications of the analysis outside the simplified setting of the stylized model

forecasting the var of crude oil market do alternative distributions help abstract accurate modeling of the empirical distribution of crude oil market returns is extremely important in estimating risk measures in addition to several commonly used distributions alternative distributions are explored in this study some of which account for the asymmetry and heavy tails simultaneously found in distributions and contain more tail parameters to separately depict the right and left tails when forecasting the value at risk var of crude oil markets during highly volatile periods seven backtests are also conducted to compare the var forecasting accuracy among different distributions the empirical results indicate that a highly volatile environment challenges the commonly used distributions and the four risk models based on commonly used distributions are rejected about 27 to 38 of the time the alternative distributions i e skewed general error distributions sged generalized hyperbolic skewed student t distributions ghst and generalized asymmetric student t gast distributions generally produce more accurate var measurement and gast gives the best measurement accuracy the empirical results imply that risk managers or policymakers should further consider more flexible distributions such as sged ghst or gast in particular when quantifying or managing the risk in turbulent market times

implications of nonlinear dynamics for financial risk management this paper demonstrates that when log price changes are not iid their conditional density may be more accurate than their unconditional density for describing short term behavior using the bds test of independence and identical distribution daily log price changes in four currency futures contracts are found to be not iid while there appear to be no predictable conditional mean changes conditional variances are predictable and can be described by an autoregressive volatility model that seems to capture all the departures from independence and identical distribution based on this model daily log price changes are decomposed into a predictable part which is described parametrically by the autoregressive volatility model and an unpredictable part which can be modeled by an empirical density either parametrically or nonparametrically this two step seminonparametric method yields a conditional density for daily log price changes which has a number of uses in financial risk management

the choice of the distribution of asset returns how extreme value theory can help abstract one of the issues of risk management is the choice of the distribution of asset returns academics and practitioners have assumed for a long time for more than three decades that the distribution of asset returns is a gaussian distribution such an assumption has been used in many fields of finance building optimal portfolio pricing and hedging derivatives and managing risks however real financial data tend to exhibit extreme price changes such as stock market crashes that seem incompatible with the assumption of normality this article shows how extreme value theory can be useful to know more precisely the characteristics of the distribution of asset returns and finally help to chose a better model by focusing on the tails of the distribution an empirical analysis using equity data of the us market is provided to illustrate this point

the welfare costs of price controls for cars and color televisions in poland contrasting estimates of rent seeking from recent experience the welfare costs of price controls can vary enormously depending on the method of allocating the goods in shortage and the possible rent seeking costs that may result with full rent dissipation the welfare loss from price controls on polish color televisions in 1989 was about ten times the standard estimates of distortion costs which ignore rent seeking and was more than 100 percent of the value of domestic producers sales the methods of allocating cars however did not result in rent seeking costs the domestic price controls were an unintended implicit subsidy to imports subsidies for cars were estimated at 43 percent and for color televisions at 22 percent

the tail risk premia of the carry trades abstract we study the relationship between the excess returns of portfolios invested in carry trade positions and an innovative global tail risk factor we find that high interest rate currencies are related to innovations in global currency tail risk they deliver low returns in times of unexpected high tail risk and high returns in times of unexpected low tail risk suggesting a standard asset pricing theory approach to explain the returns to the carry trade our tail risk factor can be understood as the interaction of moment based factors such as volatility skewness and kurtosis our results tend to indicate that the interaction of moments i e tail risk rather than the moments alone drives investor behavior this makes sense since the ultimate risk for carry traders is to reach their funding limits which are set because of the regulations on the back of tail risk statistics value at risk and not simply on the back of the volatility the skewness or the kurtosis alone the result holds in other cross sections of currencies and whether the global tail risk indicators are estimated in the currency the equity or the bond market

market risk management in a post basel ii regulatory environment we propose a novel method of mean capital requirement portfolio optimization the optimization is performed using a parallel framework for optimization based on the nondominated sorting genetic algorithm ii capital requirements for market risk include an additional stress component introduced by the recent basel 2 5 regulation our optimization with the basel 2 5 formula in the objective function produces superior results to those of the old basel ii formula in stress scenarios in which the correlations of asset returns change considerably these improvements are achieved at the expense of reduced cardinality of pareto optimal portfolios this reduced cardinality and thus portfolio diversification in periods of relatively low market volatility may have unintended consequences for banks risk exposure

how resilient is the german banking system to macroeconomic shocks abstract macroeconomic stress testing studies often rely on rather short sample periods due to the limited availability of banking data they may fail to appropriately account for the cyclicality in the interaction between the banking system and macroeconomic developments in this paper we use a newly constructed data set on german banks income and loss statements over the past 39 years to model the interaction between the banking sector and the macroeconomy our var analysis indicates that the level of stress in the banking sector is strongly affected by monetary policy shocks the results rationalize the active behavior of central banks observed during periods of financial market crises

anomalies in green national accounting we extend standard arguments for greening the product side of the national accounts to the income side of the accounts and turn up an anomaly for an economy with oil use no entry for oil income a supposed primary factor appears in the income side of the national accounts when the depletion of natural capital is accounted for on the product side of the accounts we resolve this issue by applying an income definition developed in the theory of national accounting this however leads to another anomaly on the income side of the national accounts

population growth and natural resource scarcity long run development under seemingly unfavorable conditions in this paper i consider an economy that is constrained by the use of natural resources and driven by knowledge accumulation resources are essential inputs in all sectors i show that population growth and poor input substitution are not detrimental but on the contrary are even necessary to obtain a sustainable consumption level i find a general rule to define the conditions for a constant innovation rate the rule does not apply to capital but to labor growth which is the crucial input in research furthermore the rule relates to the sectoral structure of the economy and to demographic transition the results continue to hold with a backstop technology and are extended for the case of minimum resource constraints

when more is less using multiple constraints to reduce tail risk abstract financial institutions suffered large trading losses during the 2007 2009 global financial crisis these losses cast doubt on the effectiveness of regulations and risk management systems based on a single value at risk var constraint while some researchers have recommended using conditional value at risk cvar to control tail risk var remains popular among practitioners and regulators accordingly our paper examines the effectiveness of multiple var constraints in controlling cvar under certain conditions we theoretically show that they are more effective than a single var constraint furthermore we numerically find that the maximum cvar permitted by the constraints is notably smaller than with a single constraint these results suggest that regulations and risk management systems based on multiple var constraints are more effective in reducing tail risk than those based on a single var constraint

incentives for effective risk management under the new capital accord banks choose between two different types of risk management systems the standard or the internal rating based approach the paper considers how a bank s preference for a risk management system is affected by the presence of supervision by bank regulators the model uses a principal agent setting between a bank s owner and its risk management the main conclusion is that previously unregulated institutions can be expected to switch to the lower quality standard approach subsequent to becoming regulated i e the presence of regulation may induce a bank to decrease the quality of its risk management system

another look at models of the short term interest rate the short term rate of interest is fundamental to much of theoretical and empirical finance yet no consensus has emerged on the dynamics of its volatility we show that models which parameterize volatility only as a function of interest rate levels tend to over emphasize the sensitivity of volatility to levels and fail to model adequately the serial correlation in condi tional variances on the other hand serial correlation based models like garch models fail to capture adequately the relationship between interest rate levels and volatility we introduce and test a new class of models for the dynamics of short term interest rate volatility which allows volatility to depend on both interest rate levels and information shocks two important conclusions emerge first the sensitivity of interest rate volatility to interest rate levels has been overstated in the literature while this relationship is important adequately modeling volatility as a function of unexpected information shocks is also important sec ond we conclude that the volatility processes in many existing theoretical models of interest rates are misspecified and suggest new paths toward improving the theory

risk models at risk the experience from the global financial crisis has raised serious concerns about the accuracy of standard risk measures as tools for the quantification of extreme downward risks a key reason for this is that risk measures are subject to a model risk due e g to specification and estimation uncertainty while regulators have proposed that financial institutions assess the model risk there is no accepted approach for computing such a risk we propose a remedy for this by a general framework for the computation of risk measures robust to model risk by empirically adjusting the imperfect risk forecasts by outcomes from backtesting frameworks considering the desirable quality of var models such as the frequency independence and magnitude of violations we also provide a fair comparison between the main risk models using the same metric that corresponds to model risk required corrections

investing exhaustible resource rents and the path of consumption we set out dollar valued net national product for an economy with a wasting essential stock oil deposit we take up maintaining capital intact and locally unchan ging consumption the percentage change in net investment or genuine savings relative to the market rate of interest denotes whether current consumption is rising

generating volatility forecasts from value at risk estimates statistical volatility models rely on the assumption that the shape of the conditional distribution is fixed over time and that it is only the volatility that varies the recently proposed conditional autoregressive value at risk caviar models require no such assumption and allow quantiles to be modeled directly in an autoregressive framework although useful for risk management caviar models do not provide volatility forecasts such forecasts are needed for several other important applications such as option pricing and portfolio management it has been found that for a variety of probability distributions there is a surprising constancy of the ratio of the standard deviation to the interval between symmetric quantiles in the tails of the distribution such as the 0 025 and 0 975 quantiles this result has been used in decision and risk analysis to provide an approximation of the standard deviation in terms of quantile estimates provided by experts drawing on the same result we construct financial volatility forecasts as simple functions of the interval between caviar forecasts of symmetric quantiles forecast comparison using five stock indices and 20 individual stocks shows that the method is able to outperform generalized autoregressive conditional heteroskedasticity garch models and moving average methods