income and the use of prescription drugs by the elderly evidence from the notch cohorts we use exogenous variation in social security payments created by the social security benefits notch to estimate how retirees use of prescription medications responds to changes in their incomes using data from the 1993 wave of the ahead we obtain instrumental variables estimates of the income elasticity of prescription drug use that are uniformly above 1 00 with a middle estimate of 1 32 simulations based on our estimates suggest that reductions in social security benefits similar to those incorporated in recent reform proposals would significantly reduce prescription drug use among the elderly

buffer stocks and precautionary savings with loss aversion abstract this paper reexamines buffer stocks and precautionary savings in the presence of loss aversion we assume that agents are disappointment averse as in gul econometrica 59 1991 667 686 we show that the concavity of the marginal utility continues to determine precautionary saving but its effect is of a second order magnitude proportional to the square of the coefficient of variation compared to the first order effect proportional to the coefficient of variation induced by loss aversion we show that a stabilization fund that is rather small when agents are maximizing the conventional expected utility turns out to be rather large with loss aversion

jumps and stochastic volatility in crude oil futures prices using conditional moments of integrated volatility we evaluate alternative models of the volatility of commodity futures prices based on high frequency intraday data from the crude oil futures markets for the october 2001 december 2012 period these models are implemented with a simple gmm estimator that matches sample moments of the realized volatility to the corresponding population moments of the integrated volatility models incorporating both stochastic volatility and jumps in the returns series are compared on the basis of the overall fit of the data over the full sample period and subsamples we also find that jumps in the returns series add to the accuracy of volatility forecasts

the importance of the volatility risk premium for volatility forecasting in this paper we study the role of the volatility risk premium for the forecasting performance of implied volatility we introduce a non parametric and parsimonious approach to adjust the model free implied volatility for the volatility risk premium and implement this methodology using more than 20 years of options and futures data on three major energy markets using regression models and statistical loss functions we find compelling evidence to suggest that the risk premium adjusted implied volatility significantly outperforms other models including its unadjusted counterpart our main finding holds for different choices of volatility estimators and competing time series models underlying the robustness of our results

economic determinants of oil futures volatility a term structure perspective to assess the economic determinants of oil futures volatility we firstly develop and estimate a multi factor oil futures pricing model with stochastic volatility that is able to disentangle long term medium term and short term variations in commodity markets volatility the volatility estimates reveal that in line with theory the volatility factors are unspanned persistent and carry negative market price of risk while crude oil markets are becoming more integrated with financial markets after 2004 short term volatility is driven by industrial production term and credit spreads the s p 500 and the us dollar index along with the traditional drivers including hedging pressure and vix medium term volatility is consistently related to open interest and credit spreads while after 2004 oil sector variables such as inventory and consumption also impact this part of the term structure interest rates mostly matter for long term futures price volatility

stochastic convenience yield and the pricing of oil contingent claims this paper develops and empirically tests a two factor model for pricing financial and real assets contingent on the price of oil the factors are the spot price of oil and the instantaneous convenience yield the parameters of the model are estimated using weekly oil futures contract prices from january 1984 to november 1988 and the model s performance is assessed out of sample by valuing futures contracts over the period november 1988 to may 1989 finally the model is applied to determine the present values of one barrel of oil deliverable in one to ten years time

economic linkages relative scarcity and commodity futures returns this paper shows that economic linkages among commodities create a source of long term correlation between futures returns we extend the theory of storage to a multi commodity level and find that the convenience yield of a commodity depends on its relative scarcity with respect to other related commodities this implies a feedback effect between commodities that is necessary to replicate the upward sloping correlation term structure of futures returns observed for related commodities we present a multi commodity affine model that validates our theoretical predictions and considerably reduces the pricing errors in out of sample crack spread options the author 2012 published by oxford university press on behalf of the society for financial studies all rights reserved for permissions please e mail journals permissions oup com oxford university press

how important is precautionary saving we estimate how much of the wealth of a sample of psid respondents is held because some households face more income uncertainty than others we begin by solving a theoretical model of saving which we use to develop appropriate measures of uncertainty we then regress measures of wealth on our measures of uncertainty and find evidence that households engage in precautionary saving finally we simulate the wealth distribution that our empirical results imply would prevail if all households had the same uncertainty as the lowest uncertainty group we find that between 39 and 46 percent of wealth in our sample is attributable to the extra uncertainty that some consumers face compared to the lowest uncertainty group

the effect of female education on fertility and infant health evidence from school entry policies using exact date of birth this paper uses age at school entry policies to identify the effect of female education on fertility and infant health we focus on sharp contrasts in schooling fertility and infant health between women born just before and after the school entry date school entry policies affect female education and the quality of a woman s mate and have generally small but possibly heterogeneous effects on fertility and infant health we argue that school entry policies manipulate primarily the education of young women at risk of dropping out of school

the price elasticity of demand for pharmaceuticals amongst high income older australians a natural experiment most high income older australians became eligible for a pharmaceutical concession through a 1999 policy change i exploit this natural experiment to estimate their price elasticity of demand for pharmaceuticals the preferred model is a nonlinear instrumental variable iv regression estimated on nationally representative repeated cross sectional survey data using the generalized method of moments gmm no significant evidence is found for endogenous take up and so cross sectional estimates are also considered taking all of the results into account the headline estimate is 0 1 implying that quantity demanded is not highly responsive to price

bond pricing and the term structure of interest rates a new methodology for contingent claims valuation this paper presents a unifying theory for valuing contingent claims under a stochastic term structure of interest rates the methodology based on the equivalent martingale measure technique takes as given an initial forward rate curve and a family of potential stochastic processee for its subsequent movements a no arbitrage condition restricts this family of processes yielding valuation formulae for interest rate sensitive contingent claims which do not explicitly depend on the market prices of risk examples are provided to illustrate the key results in relation to the term structure of interest rates arbitrage pricing theory has two purposes the first is to price all zero coupon default free bonds of varying maturities from a finite number of economic fundamentals called state variables the second is to price all interest rate sensitive contingent claims taking as given the prices of the zero coupon bonds this paper presents a general theory and a unifying framework for understanding arbitrage pricing theory in this context of which all existing arbitrage pricing models are special cases in particular vasicek 1977 brennan and schwartz 1979 langetieg 1980 ball and torous 1983 ho and lee 1986 schaefer and schwartz 1987 and artzner and delbaen 1988 the primary contribution of this paper however is a new methodology for solving the second problem i e the pricing of interest rate sensitive contingent claims given the prices of all zero coupon bonds the methodology is new because i it imposes its stochastic structure directly on the evolution of the forward rate curve ii it does not require an inversion of the term structure to eliminate the market prices of risk from contingent claim values and iii it has a stochastic spot rate process with multiple stochastic factors influencing the term structure the model can be used to consistently price and hedge all contingent claims american or european on the term structure and it is derived from necessary and more importantly sufficient conditions for the absence of arbitrage the arbitrage pricing models of vasicek 1977 brennan and schwartz 1979 langetieg 1980 and artzner and delbaen 1988 all require an iformerly titled bond pricing and the term structure of interest rates a new methodology

equilibrium price dynamics of emission permits this article presents a stochastic equilibrium model for environmental markets that allows us to study the characteristic properties of emission permit prices induced by the design of today s cap and trade systems we characterize emission permits as highly nonlinear contingent claims on economy wide emissions and reveal their hybrid nature between investment and consumption assets our model makes predictions about the dynamics and volatility structure of emission permit prices the forward price curve and the implications for option pricing in this market empirical evidence from existing emissions markets shows that the model explains the stylized facts of emission permit prices and related derivatives

risk premia and seasonality in commodity futures we develop and estimate a multifactor a ne model of commodity futures that allows for stochastic variations in seasonality we show conditions under which the yield curve and the cost of carry curve adopt augmented nelson and siegel functional forms this restricted version of the model is parsimonious does not suer from identi cation problems and matches well the yield curve and futures curve over time we estimate the model using heating oil futures prices over the period 1984 2012 we nd strong evidence of stochastic seasonality in the data we analyze risk premia in futures markets and discuss two traditional theories of commodity futures the theory of storage and the theory of normal backwardation the data strongly support the theory of storage

household saving micro theories and micro facts in this survey we review the recent theoretical and empirical literature on household saving and consumption the discussion is structured around a list of motives for saving and how well the standard theory captures these motives we show that almost all of the motives for saving that have been suggested in the informal saving literature can be captured in the standard optimizing model particular attention is given to recent work on the precautionary motive and its implications for saving and consumption behavior we also discuss the behavioral or psychological approach that eschews the use of standard optimization techniques and focuses instead on direct consideration on saving we provide a section on facts who save and how much we then discuss informally the recent decline in the u s saving rate and whether the theory is of much use in understanding this and other changes in aggregate saving rates over time we do not find any convincing explanation for the change in saving rates we also discuss some analyses of saving behavior over the life cycle addressing such questions as whether households save enough for retirement and whether the consumption patterns of older households can be rationalized within a simple life cycle model we also review a great number of studies of the consumption euler equations based on our analysis of the studies cited we conclude that there is still mixed evidence that consumption is excessively sensitive to income we also examine in depth the recent empirical literature on the precautionary motive we conclude that although some households do seem to have a significant precautionary motive at some points in their life cycle this motive is not so strong empirically as some investigators suggest

should investors include commodities in their portfolios after all new evidence abstract this paper investigates whether an investor is made better off by including commodities in a portfolio that consists of traditional asset classes first we revisit the posed question within an in sample setting by employing mean variance and non mean variance spanning tests then we form optimal portfolios by taking into account the higher order moments of the portfolio returns distribution and evaluate their out of sample performance under the in sample setting we find that commodities are beneficial only to non mean variance investors however these benefits are not preserved out of sample our findings challenge the alleged diversification benefits of commodities and are robust across a number of performance evaluation measures utility functions and datasets the results hold even when transaction costs are considered and across various sub periods not surprisingly the only exception appears over the 2005 2008 unprecedented commodity boom period

health behavior health knowledge and schooling the positive correlation between schooling and good health is well documented one explanation is that schooling helps people choose healthier life styles by improving their knowledge of the relationship between health behaviors and health outcomes that is schooling improves the household s allocative efficiency in producing health this empirical study uses direct measures of health knowledge to test this explanation part of the relationship between schooling and the consumption of cigarettes alcohol and exercise is explained by differences in health knowledge however most of schooling s effects on health behavior remain after differences in knowledge are controlled for

income and the utilization of long term care services evidence from the social security benefit notch this paper estimates the impact of income on the long term care utilization of elderly americans using a natural experiment that led otherwise similar retirees to receive significantly different social security payments based on their year of birth using data from the 1993 and 1995 waves of the ahead we estimate instrumental variables models and find that a positive permanent income shock lowers nursing home use but increases the utilization of paid home care services we find some suggestive evidence that the effects are due to substitution of home care for nursing home utilization the magnitude of these estimates suggests that moderate reductions in post retirement income would significantly alter long term utilization patterns among elderly individuals

seasonal stochastic volatility implications for the pricing of commodity options many commodity markets contain a strong seasonal component not only at the price level but also in volatility in this paper the importance of seasonal behavior in the volatility for the pricing of commodity options is analyzed we propose a seasonally varying long run mean variance process that is capable of capturing empirically observed patterns semi closed form option valuation formulas are derived we then empirically study the impact of the proposed seasonal stochastic volatility model on the pricing accuracy of natural gas futures options traded at the new york mercantile exchange nymex and corn futures options traded at the chicago board of trade cbot our results demonstrate that allowing stochastic volatility to fluctuate seasonally significantly reduces pricing errors for these contracts

the information content of a nonlinear macro finance model for commodity prices state of the art term structure models of commodity prices have serious difficulties extrapolating the prices of long maturity futures contracts from short dated contracts this situation is problematic for valuing real commodity linked assets we estimate a nonlinear four factor continuous time model of commodity price dynamics the model nests many previous specifications to estimate the model we use crude oil prices and inventories the inventory data and nonlinear price dynamics have a large impact on oil price forecasts the additional factor in our model compared with current three factor models has a significant impact on model implied long maturity futures prices received november 23 2015 editorial decision september 12 2016 by editor geert bekaert

jump and variance risk premia in the s p 500 abstract we analyze the risk premia embedded in the s p 500 spot index and option markets we use a long time series of spot prices and a large panel of option prices to jointly estimate the diffusive stock risk premium the price jump risk premium the diffusive variance risk premium and the variance jump risk premium the risk premia are statistically and economically significant and move over time investigating the economic drivers of the risk premia we are able to explain up to 63 of these variations

social security income and health care spending evidence from the social security notch the paper exploits social security legislation changes to identify the causal effect of social security income on out of pocket medical expenditures of the elderly using the 1986 1994 consumer expenditure survey and an instrumental variables strategy the empirical results show that health care expenditures are responsive to changes in social security income for elderly individuals with less than a high school education the estimated income elasticities are between 1 41 and 3 47 depending on the outcome measures and are statistically significant at conventional levels the findings are in contrast to existing studies that find a small income elasticity at the individual household level this article is protected by copyright all rights reserved

investing in health the long term impact of head start on smoking i introduction there is a strong evidence that early childhood socioeconomic conditions have long term economic consequences reinforcing and sustaining disparities over the lifecourse 1 this observation provides a compelling rationale for public investments targeted toward disadvantaged children to expand opportunities and break the cycle of poverty head start is the principal federally funded program through which the united states invests directly in the human capital of disadvantaged preschool children since its inception in 1965 as part of president lyndon johnson s war on poverty head start has provided services to more than 23 million preschool children in 2005 there were more than 900 000 children enrolled in the program at a total cost of 6 8 billion office of head start 2006a to achieve its overall goal of increasing the school readiness of participants head start provides a comprehensive set of services including education health nutritional and social services to participants and their families research has shown that head start has positive impacts on participants human capital both in childhood and in adulthood 2 in recent years questions have arisen about the relative effectiveness of head start and whether it should be continued in its present form u s department of health and human services 2003 much of the debate has centered on the magnitude and persistence of the cognitive achievements of head start participants however given the link between education and health 3 and the comprehensive nature of head start with substantial health components one could reasonably expect it to have a favorable impact on participants health as well as education if significant health effects were found to persist into adulthood this in itself could alter the evaluation of head start and have important implications for the associated policy debate smoking is the leading preventable cause of mortality in the united states mokdad et al 2004 it is linked to an extensive list of diseases chaloupka and warner 2000 and imposes large economic costs on society centers for disease control and prevention 2002 tobacco use generally begins before individuals graduate high school and as an addictive behavior youth smoking is linked to adult smoking u s department of health and human services 1994 adolescents from low socioeconomic status households with low academic achievement are more likely to use tobacco products u s department of health and human services 1994 thus comprehensive development programs targeted toward disadvantaged youths that are designed to improve child outcomes have the potential to influence smoking improve health over the lifecourse and reduce the social costs from smoking suggestive evidence that head start might influence the smoking behavior of participants comes from evaluations of other preschool programs that targeted low income children participants in both the carolina abecedarian preschool program and the high scope perry preschool program were much less likely to smoke as adults barnett and masse 2007 belfield et al 2006 in this article we assess the impact of head start participation on adult smoking behavior using data from the panel study of income dynamics psid and its supplements on early childhood education and health we examine the cohort of adults above age 21 in 1999 whose age is low enough to have potentially participated in a head start program following currie and thomas 1995 and garces thomas and currie 2002 we employ a sibling based model to control for unobservable family characteristics that may affect smoking or the decision to participate in head start our results show that head start participation significantly influences smoking related behavior we estimate that if head start participants had not enrolled in the program these individuals would be approximately 20 percentage points more likely to smoke cigarettes beyond age 25

the economic value of realized volatility using high frequency returns for option valuation many studies have documented that daily realized volatility estimates based on intraday returns provide volatility forecasts that are superior to forecasts constructed from daily returns only we investigate whether these forecasting improvements translate into economic value added

oil futures prices in a production economy with investment constraints we document a new stylized fact that the relationship between the volatility of oil futures prices and the slope of the forward curve is nonmonotone and has a v shape this pattern cannot be generated by standard models that emphasize storage we develop an equilibrium model of oil production in which investment is irreversible and capacity constrained investment constraints affect firms investment decisions and imply that the supply elasticity changes over time since demand shocks must be absorbed by changes in prices or changes in supply time varying supply elasticity results in time varying volatility of futures prices estimating this model we show it is quantitatively consistent with the v shape relationship between the volatility of futures prices and the slope of the forward curve in recent years commodity markets have experienced dramatic growth in trad

the determinants of mortality mortality rates have fallen dramatically over time starting in a few countries in the 18th century and continuing to fall today in just the past century life expectancy has increased by over 30 years at the same time mortality rates remain much higher in poor countries with a difference in life expectancy between rich and poor countries of also about 30 years this difference persists despite the remarkable progress in health improvement in the last half century at least until the hiv aids pandemic in both the time series and the cross section data there is a strong correlation between income per capita and mortality rates a correlation that also exists within countries where richer better educated people live longer we review the determinants of these patterns over history over countries and across groups within countries while there is no consensus about the causal mechanisms we tentatively identify the application of scientific advance and technical progress some of which is induced by income and facilitated by education as the ultimate determinant of health such an explanation allows a consistent interpretation of the historical cross country and within country evidence we downplay direct causal mechanisms running from income to health

computing the market price of volatility risk in the energy commodity markets abstract in this paper we demonstrate the need for a negative market price of volatility risk to recover the difference between black scholes black f scholes m 1973 the pricing of options and corporate liabilities journal of political economy 81 637 654 black black f 1976 studies of stock price volatility changes in proceedings of the 1976 meetings of the business and economics statistics section american statistical association pp 177 181 implied volatility and realized term volatility initially using quasi monte carlo simulation we demonstrate numerically that a negative market price of volatility risk is the key risk premium in explaining the disparity between risk neutral and statistical volatility in both equity and commodity energy markets this is robust to multiple specifications that also incorporate jumps next using futures and options data from natural gas heating oil and crude oil contracts over a 10 year period we estimate the volatility risk premium and demonstrate that the premium is negative and significant for all three commodities additionally there appear distinct seasonality patterns for natural gas and heating oil where winter withdrawal months have higher volatility risk premiums computing such a negative market price of volatility risk highlights the importance of volatility risk in understanding priced volatility in these financial markets

social security and elderly homeownership abstract over the last twenty five years the homeownership rate of households 65 years and older has risen steadily while the homeownership rate for 35 64 year old households has remained relatively unchanged at the same time the real value of social security benefits has risen substantially using data from the march 1978 to 2001 current population surveys this paper documents the evolution and assesses the causal role of the social security program in increasing elderly homeownership to isolate the causal effect the analysis develops an instrumental variable approach that relies on the large variation in benefits for birth cohorts from 1900 to 1930 due to double indexation of the system and the so called social security notch for all elderly the estimated elasticity of homeownership to social security benefits ranges from 0 26 to 0 49 across marital groups the widowed have the greatest responsiveness to benefits increases in benefits also increase household formation among the elderly overall the estimates indicate that between half and as much as all of the time series rise in elderly homeownership over the last twenty five years can be attributable to the rise in social security benefits and suggest that reductions in benefits would alter homeownership among the elderly significantly

loss aversion in a consumption savings model abstract we propose a model of consumption and saving based on kahneman and tversky s prospect theory that implies a fundamental asymmetry in consumption behavior inconsistent with other models of consumption when there is sufficient income uncertainty a person resists lowering consumption in response to bad news about future income this resistance is greater than the resistance to increasing consumption in response to good news we present empirical evidence from five countries that confirms this behavior

short term variations and long term dynamics in commodity prices in this article we develop a two factor model of commodity prices that allows meanreversion in short term prices and uncertainty in the equilibrium level to which prices revert although these two factors are not directly observable they may be estimated from spot and futures prices intuitively movements in prices for long maturity futures contracts provide information about the equilibrium price level and differences between the prices for the short and long term contracts provide information about short term variations in prices we show that although this model does not explicitly consider changes in convenience yields over time this short term long term model is equivalent to the stochastic convenience yield model developed in gibson and schwartz 1990 we estimate the parameters of the model using prices for oil futures contracts and apply the model to some hypothetical oil linked assets to demonstrate its use and some of its advantages over the gibson schwartz model

unspanned stochastic volatility and fixed income derivatives pricing we propose a parsimonious unspanned stochastic volatility model of the term structure and study its implications for fixed income option prices the drift and quadratic variation of the short rate are affine in three state variables the short rate its long term mean and variance which follow a joint markov vector process yet bond prices are exponential affine functions of only two state variables independent of the current interest rate volatility level because this result holds for an arbitrary volatility process such a process can be calibrated to match fixed income derivative prices furthermore this model can be extended by relaxing the time homogeneity to fit any arbitrary term structure in its hjm form this model nests the analogous stochastic equity volatility model of heston 190 heston s l 1993 a closed form solution for options with stochastic volatility review of financial studies 6 327 343 in particular if the volatility process is specified to be affine closed form solutions for interest rate options obtain we propose an efficient algorithm to compute these prices an application using data on caps and floors shows that the model can capture very well the implied black spot volatility surface while simultaneously fitting the observed term structure c 2005 elsevier b v all rights reserved

the dynamics of the forward interest rate curve a formulation with state variables the objective of this paper is twofold first the paper develops a class of models of the term structure of interest rates in the heath jarrow and morton 1992 framework with dynamics characterized by the evolution of a small set of state variables second the paper exploits this characterization of the dynamics of the term structure in an estimation exercise that makes use of both the time series and cross section of bond prices in this way our class of models bridges the gap between traditional models such as cox ingersoll and ross 1985 and vasicek 1977 that emphasize the dynamics of interest rates and the models of heath jarrow and morton 1992 that stress fitting the cross section of bond prices

income and health spending evidence from oil price shocks health expenditures as a share of gdp in the united states have more than tripled over the past half century a common conjecture is that this is a consequence of rising income we investigate this hypothesis by instrumenting for local area income with time series variation in oil prices interacted with local oil reserves this strategy enables us to capture both partial equilibrium and local general equilibrium effects of income on health expenditures our central income elasticity estimate is 0 7 with 1 1 as the upper end of the 95 confidence interval which suggests that rising income is unlikely to be a major driver of the rising health expenditure share of gdp 2013 the president and fellows of harvard college and the massachusetts institute of technology

optimal saving rules for loss averse agents under uncertainty abstract most empirical studies assume only monotonic preferences for households behavioral research however provides substantial evidence that preferences for wealth are measured relative to a reference point in this paper we introduce and solve a two period consumption and savings model for a loss averse agent who measures utility from consumption relative to a benchmark level the solution is given as a parametric decision rule with one unknown parameter that depends on the distribution of the return on saving we find non linearity in the fraction of wealth saved where the specific saving pattern depends on the sign of the real return on savings the amount of saving is nondecreasing in initial wealth and the riskiness of the return distribution

the effect of social security on labor supply a cohort analysis of the notch generation this article uses aggregate birth year calendar year level data derived from the current population survey cps to estimate the effect of social security wealth on the labor supply of older men in the 1970s and 1980s the analysis focuses on measuring the impact of the 1977 amendments to the social security act which created a substantial unanticipated reduction in social security wealth for individuals born after 1916 this differential in benefits has become known as the benefit notch results indicate that labor supply continued to decline for the notch babies who received lower social security benefits than earlier cohorts

the factor structure in equity options principal component analysis of equity options on dow jones rms reveals a strong factor structure the rst principal component explains 77 of the variation in the equity volatility level 77 of the variation in the equity option skew and 60 of the implied volatility term structure across equities furthermore the rst principal component has a 92 correlation with sp g12 g13

valuation of commodity futures and options under stochastic convenience yields interest rates and jump diffusions in the spot this paper investigates the effects of stochastic convenience yields stochastic interest rates and jumps in the spot price on the pricing of commodity futures forwards and futures options numerical examples show that one factor prices differ materially from the stochastic convenience yield two factor prices when convenience yield is considerably above its long term average the extension to a three factor model with stochastic interest rates leads to a different futures price but the forward price is unchanged the extension ofthe three factor model to include jumps in the spot price process does not affect forward or futures prices but it can have an impact on options prices the model is applied to price the present value of future cash flows from a real asset

equilibrium exhaustible resource price dynamics we develop equilibrium models of exhaustible resource markets with endogenous extraction choices and prices our analysis demonstrates how adjustment costs can generate oil and gas forward price dynamics with two factors consistent with the behavior these commodities exhibit in the schwartz and smith 2000 calibration our two factor model predicts that stochastic volatility will arise in these markets as a natural consequence of production adjustments however and we provide supporting empirical evidence differences between endogenous price processes from our general equilibrium model and exogenous processes in earlier papers can generate significant differences in both financial and real option values

forecasting the volatility of crude oil futures using har type models with structural breaks abstract we introduce sixteen har type volatility models with structural breaks and estimate their parameters by applying 5 min high frequency transaction data for wti crude oil futures we find significant structural breaks in the volatility of crude oil futures additionally the historical realized volatility continuous sample path variation negative realized semivariance signed jump signed semi jump and leverage components contain substantial and salient information for forecasting the volatility of crude oil futures then we use loss functions to assess the forecasting performance of these sixteen new models and finally rank these models using the promethee ii method our results indicate that different models exhibit different predictive power in forecasting the 1 day 1 week and 1 month volatility of crude oil futures of the new har type models the new har rsv model performs best at forecasting the 1 day and 1 month volatilities whereas the new har cj best forecasts the 1 week volatility

do bonds span the fixed income markets theory and evidence for unspanned stochastic volatility most term structure models assume bond markets are complete that is that all fixed income derivatives can be perfectly replicated using solely bonds however we find that in practice swap rates have limited explanatory power for returns on at the money straddles portfolios mainly exposed to volatility risk we term this empirical feature unspanned stochastic volatility usv while usv can be captured within an hjm framework we demonstrate that bivariate models cannot exhibit usv we determine necessary and sufficient conditions for trivariate markov affine systems to exhibit usv for such usv models bonds alone may not be sufficient to identify all parameters rather derivatives are needed

humps in the volatility structure of the crude oil futures market new evidence abstract this paper analyses the volatility structure of commodity derivatives markets the model encompasses hump shaped unspanned stochastic volatility which entails a finite dimensional affine model for the commodity futures curve and quasi analytical prices for options on commodity futures using an extensive database of crude oil futures and futures options spanning 21 years we find the presence of hump shaped partially spanned stochastic volatility in the crude oil market the hump shaped feature is more pronounced when the market is more volatile and delivers better pricing as well as hedging performance under various dynamic factor hedging schemes

social security and elderly living arrangements evidence from the social security notch previous studies of the effect of social security on elderly living arrangements generally have relied on data from the distant past or differences in benefits across families or cohorts that potentially were correlated with other determinants of living arrangements using data from the 1980 99 current population surveys we attempt to isolate the causal effect of social security on living arrangements with an instrumental variable approach that relies on the large shifts in benefits for cohorts born from 1910 21 the socalled social security notch over all elderly households the estimated elasticity of living with others with respect to social security income is 0 4 with elasticities of 1 3 and 1 4 for the widowed and divorced respectively most of the effects on living arrangements appear to be concentrated among the lesser educated as well our estimated elasticities are substantially larger than those from previous studies and suggest that reductions in current benefits would alter living arrangements significantly

social security income and the utilization of home care evidence from the social security notch this paper exploits social security law changes to identify the effect of social security income on the use of formal and informal home care by the elderly results from an instrumental variables estimation strategy show that as retirement income increases elderly individuals increase their use of formal home care and become less likely to rely on informal home care provided to them by their children this negative effect on informal home care is most likely driven by male children withdrawing from their caregiving roles the empirical results also suggest that higher social security benefits would encourage the use of formal home care by those who would not have otherwise used any type of home care and would also encourage the use of both types of home care services among elderly individuals

modelling the dynamics of bitcoin and litecoin garch versus stochastic volatility models abstractwe examine and compare a large number of generalized autoregressive conditional heteroskedastic garch and stochastic volatility sv models using series of bitcoin and litecoin price retu

from the samuelson volatility effect to a samuelson correlation effect an analysis of crude oil calendar spread options abstract our first aim in this paper is to introduce a futures based model able of capturing the main features displayed by crude oil futures and options contracts such as the samuelson volatility effect and the volatility smile we calculate the joint characteristic function of two futures contracts in the model in analytic form and use it to price calendar spread options in an empirical application we show that the model in contrast to simpler nested models can be successfully calibrated to market prices of vanilla and calendar spread options our second aim is to use this model to analyze the dependence structure of crude oil futures contracts to this end we propose analytical expressions giving the copula and copula density directly in terms of the joint characteristic function these tools allow us to perform an in depth analysis for pairs of futures and we observe a phenomenon we call the samuelson correlation effect

dynamic speculation and hedging in commodity futures markets with a stochastic convenience yield the main objective of this paper is to address in an a continuous time framework the issue of using storable commodity futures as vehicles for hedging purposes when in particular the convenience yield as well as the market prices of risk evolve randomly over time following the martingale route and by operating a suitable constant relative risk aversion utility function crra specific change of numeraire we solve the investor s dynamic optimization program to obtain quasi analytical solutions for optimal demands which can be expressed in terms of two discount bonds traded and synthetic contrary to the existing literature we explicitly derive the individual optimal proportions invested in the spot commodity in a discount bond and in the futures contracts which can be computed in a simple recursive way we suggest various decompositions allowing an investor to assess the sensitivity of the optimal demands to the state variables and to specify the role played by each risky asset empirical evidence shows that the convenience yield has a strong impact on the speculation and hedging positions and the interaction among time varying risk premia determines the magnitude and the sign of these positions

a tractable framework for option pricing with dynamic market maker inventory and wealth we develop a tractable dynamic model of an index option market maker with limited capital we solve for the variance risk premium and option prices as a function of the asset dynamics and market maker option holdings and wealth the market maker absorbs end users positive demand and requires a more negative variance risk premium when she incurs losses we estimate the model using returns options and inventory and find that it performs well especially during the financial crisis the restrictions imposed by nested existing reduced form stochastic volatility models are strongly rejected in favor of the model with a market maker

price mean reversion seasonality and options markets options on agricultural commodities with maturities exceeding one year seldom trade one possible reason to explain this lack of trading is that we do not have an accurate option pricing model for products where mean reversion in spot price levels can be expected standard option pricing models assume proportionality between price variance and time to maturity this proportionality is not a valid assumption for commodities whose supply response brings prices back to production costs the model proposed here incorporates mean reversion in spot price levels and includes a correction for seasonality mean reversion and seasonality are both observed in the soybean market the empirical analysis lends strong support to the model

unspanned stochastic volatility and the pricing of commodity derivatives commodity derivatives are becoming an increasingly important part of the global derivatives market here we develop a tractable stochastic volatility model for pricing commodity derivatives the model features unspanned stochastic volatility quasi analytical prices of options on futures contracts and dynamics of the futures curve in terms of a low dimensional affine state vector we estimate the model on nymex crude oil derivatives using an extensive panel data set of 45 517 futures prices and 233 104 option prices spanning 4082 business days we find strong evidence for two predominantly unspanned volatility factors jel g13

pricing of options on commodity futures with stochastic term structures of convenience yields and interest rates we develop a model to value options on commodity futures in the presence of stochastic interest rates as well as stochastic convenience yields in the development of the model we distinguish between forward and future convenience yields a distinction that has not been recognized in the literature assuming normality of continuously compounded forward interest rates and convenience yields and log normality of the spot price of the underlying commodity we obtain closed form solutions generalizing the black scholes merton s formulas we provide numerical examples with realistic parameter values showing that both the effect of introducing stochastic convenience yields into the model and the effect of having a short time lag between the maturity of a european call option and the underlying futures contract have significant impact on the option prices

consumption puzzles and precautionary savings abstract when marginal utility is convex agents accumulate savings as a precautionary measure against labor income eventualities this paper shows that precautionary savings can go a long way in making the excess growth excess smoothness and excess sensitivity features of consumption consistent with the stochastic processes of labor income observed in the u s at the microeconomic level

towards definition of the risk premium function successful trading in electricity markets relies on the market actor s ability to accurately forecast the electricity price the fundamental electricity price models use market information provided by various price drivers including the residual that contains a risk premium in the past researchers investigating risk premium focused primarily on daily spot price levels ignoring the intraday information hindering the accurate risk premium determination this paper presents a new kgb method for modelling of risk premium based on ex ante approach focused on a yearly product the method involves a novel kgb model and its linearized formulation the kgb linear model which enables capturing the influence of renewable energy sources on risk premium the four key drivers of the kgb linear model were used providing an insight into the influence of res generation on risk premium evolution the method was tested on historical data from the german electricity market the results for the 2010 2014 period reveal overall influence of pv production share on risk premium is greater than that of wind production share both increasing the risk premium due to their variability and uncertainty using the kgb method market actors can forecast risk premium using information readily available to them

a theory of commodity price fluctuations this paper studies the price fluctuations of storable commodities that are traded in open markets and are subject to random shocks to demand or more particularly to supply it relaxes the common assumption that the shocks are identically and independently distributed in favor of temporally dependent and periodic disturbances the existence of a unique stationary rational expectations equilibrium is demonstrated for each of the models analyzed and testable implications of the models are derived an illustrative empirical investigation is then undertaken for the model with periodic disturbances using monthly time series observations for seven commodities over the period 1960 93

a multifactor stochastic volatility model of commodity prices we propose a novel representation of commodity spot prices in which the cost of carry and the spot price volatility are both driven by an arbitrary number of risk factors nesting many existing specifications the model exhibits unspanned stochastic volatility provides simple closed form expressions of commodity futures and yields analytic formulas of european options on futures we estimate the model using oil futures and options data and find that the pricing of traded contracts is accurate for a wide range of maturities and strike prices the results suggest that at least three risk factors in the spot price volatility are needed to accurately fit the volatility surface of options on oil futures highlighting the importance of using general multifactor models in pricing commodity contingent claims

risk factors and their associated risk premia an empirical analysis of the crude oil market abstract this paper sheds new light on higher order price risks in crude oil markets a model free analysis reveals that crude oil variance risk behaves fundamentally different from variance risk in equity markets most importantly a skewness swap is no valid hedge for a variance swap and investors fear large price jumps in both directions a model based assessment confirms this and reveals that while stochastic volatility is important to capture the statistical properties such as volatility clusters and time varying variance swap rates only jump risk seems to be priced with a premium empirical evidence from a pricing and hedging exercise confirms these findings

a double hurdle model of cigarette consumption this paper shows the importance of the double hurdle approach for modelling individuals cigarette consumption using data from the uk general household survey and argues that participation and consumption should be treated as separate individual choices the likelihood function for the full double hurdle is derived and it is shown how restrictions on the stochastic specification of the model and auxillary information which identifies ex smokers allow it to be decomposed the empirical results highlight the value of the sample separation information and the need to model starting and quitting as separate decisions

estimating a household production function heterogeneity the demand for health inputs and their effects on birth weight the household production literature emphasizes that technical or biological processes condition input selection by households in their production activities along with prices and income exogenous variations in health to the extent that they are perceived by individuals heterogeneity lead to correlations between inputs and health outcomes that cannot be used to derive causal conclusions therefore estimates of health technology must be obtained from a behavioral model in which health inputs are themselves choices consistent estimates are reported of the effect of endogenous inputs such as medical care smoking and fertility on birth weight and fetal growth in the presence of health heterogeneity

precautionary saving an explanation for excess sensitivity of consumption the permanent income hypothesis under certainty equivalence yields a martingale consumption process empirically this hypothesis is rejected because consumption is excessively sensitive to anticipated income one approach to account for excess sensitivity is to relax certainty equivalence by using utility functions that induce precautionary saving this article analyzes a hyperbolic absolute risk aversion utility function empirically some reasonable parameterizations of this specification allow one to match the excess sensitivity associated with the data these parameterizations also permit one to account for the excess smoothness problem excess sensitivity and excess smoothness however do not reflect the same phenomenon

valuation of vix derivatives abstract we conduct an extensive empirical analysis of vix derivative valuation models before during and after the 2008 2009 financial crisis since the restrictive mean reversion and heteroskedasticity features of existing models yield large distortions during the crisis we propose generalisations with a time varying central tendency jumps and stochastic volatility analyse their pricing performance and implications for term structures of vix futures and volatility skews we find that a process for the log of the observed vix combining central tendency and stochastic volatility reliably prices vix derivatives we also uncover a significant risk premium that shifts the long run volatility level

pricing of long dated commodity derivatives do stochastic interest rates matter abstract does modelling stochastic interest rates beyond stochastic volatility improve pricing performance on long dated commodity derivatives to answer this question we consider futures price models for commodity derivatives that allow for stochastic volatility and stochastic interest rates and a correlation structure between the underlying variables we examine the empirical pricing performance of these models on pricing long dated crude oil derivatives estimating the model parameters from historical crude oil futures prices and option prices we find that stochastic interest rate models improve pricing performance on long dated crude oil derivatives when the interest rate volatility is relatively high furthermore increasing the model dimensionality does not tend to improve the pricing performance on long dated crude oil option prices but it matters for long dated futures prices we also find empirical evidence for a negative correlation between crude oil futures prices and interest rates that contributes to improving fit to long dated crude oil option prices

commodity derivatives pricing with cointegration and stochastic covariances abstract empirically cointegration and stochastic covariances including stochastic volatilities are statistically significant for commodity prices and energy products to capture such market phenomena we develop a continuous time dynamics of cointegrated assets with a stochastic covariance matrix and derive the joint characteristic function of asset returns in closed form the proposed model offers an endogenous explanation for the stochastic mean reverting convenience yield the time series of spot and futures prices of wti crude oil and gasoline shows cointegration relationship under both physical and risk neutral measures the proposed model also allows us to fit the observed term structure of futures prices and calibrate the market implied cointegration relationship we apply it to value options on a single commodity and on multiple commodities

forecasting the good and bad uncertainties of crude oil prices using a har framework abstract good or bad uncertainty is the volatility that is associated with positive or negative innovations to asset prices this paper proposes new heterogeneous autoregressive type har type models to forecast the good and bad uncertainties of crude oil prices in this paper we investigate the effects of lagged bad and good uncertainties daily positive and negative signed jump variations and leverages on predicting good and bad uncertainties by in sample and out of sample analysis the in sample results show that bad and good uncertainties have long memory property and the predictability of long term good and bad uncertainties is stronger than that of short and mid term good and bad uncertainties the out of sample results indicate that lagged bad or good uncertainties daily positive signed jump variation and daily negative signed jump variation contain incremental out of sample information for forecasting good or bad uncertainties and in most cases lagged leverages also play indispensable roles in forecasting the good and bad uncertainties in the crude oil market moreover the results of out of sample analysis remain robust across using the other estimation window other har type models and the other sample

jumps and stochastic volatility in oil prices time series evidence abstract in this paper we examine the empirical performance of affine jump diffusion models with stochastic volatility in a time series study of crude oil prices we compare four different models and estimate them using the markov chain monte carlo method the support for a stochastic volatility model including jumps in both prices and volatility is strong and the model clearly outperforms the others in terms of a superior fit to data our estimation method allows us to obtain a detailed study of oil prices during two periods of extreme market stress included in our sample the gulf war and the recent financial crisis we also address the economic significance of model choice in two option pricing applications the implied volatilities generated by the different estimated models are compared and we price a real option to develop an oil field our findings indicate that model choice can have a material effect on the option values

seasonality and the valuation of commodity options price movements in many commodity markets exhibit significant seasonal patterns however given an observed futures price a deterministic seasonal component at the price level is not relevant for the pricing of commodity options in contrast this is not true for the seasonal pattern observed in the volatility of the commodity price analyzing an extensive sample of soybean corn heating oil and natural gas options we find that seasonality in volatility is an important aspect to consider when valuing these contracts the inclusion of an appropriate seasonality adjustment significantly reduces pricing errors in these markets and yields more improvement in valuation accuracy than increasing the number of stochastic factors

a common factor of stochastic volatilities between oil and commodity prices abstractthis article analyses the multivariate stochastic volatilities svs with a common factor influencing volatilities in the prices of crude oil and agricultural commodities used for both biofuel and nonbiofuel purposes modelling the volatility is crucial because the volatility is an important variable for asset allocation risk management and derivative pricing we develop a sv model comprising a latent common volatility factor with two asymptotic regimes with a smooth transition between them in contrast to conventional volatility models svs are generated by the logistic transformation of latent factors which comprise two components the common volatility factor and an idiosyncratic component we present a sv model with a common factor for oil corn and wheat from 8 august 2005 to 10 october 2014 using a markov chain monte carlo method to estimate the svs and extract the common volatility factor we find that the volatilities of oil and grain markets are persistent according to the estimated

an empirical model comparison for valuing crack spread options in this paper we investigate the pricing of crack spread options particular emphasis is placed on the question of whether univariate modeling of the crack spread or explicit modeling of the two underlyings is preferable therefore we contrast a bivariate garch volatility model for cointegrated underlyings with the alternative of modeling the crack spread directly conducting an empirical analysis of crude oil heating oil and crude oil gasoline crack spread options traded on the new york mercantile exchange the more simplistic univariate approach is found to be superior with respect to option pricing performance

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

a jump diffusion model for pricing and hedging with margined options an application to brent crude oil contracts abstract we develop a jump diffusion model for pricing and hedging with margined options on futures unlike a standard equity option margined options require no up front payment an attractive feature of margined options is that there is no early exercise premiums under general assumptions model parameter estimates and out of sample pricing errors are calculated using data on brent crude contracts using the same pricing technology we also hedge equity style options with margined options hedging coefficients are derived by matching an extended set of greeks we find that a target equity option can be effectively hedged using a portfolio of two margined options and the underlying as has been reported elsewhere a delta hedge is inappropriate when the underlying is a jump diffusion

competitive storage and commodity price dynamics by buying cheap and selling dear risk neutral commodity speculators can smooth commodity prices and induce serial dependence in price even when none would exist under a simple process of supply and demand commodity prices are variable and strongly positively correlated from one year to the next the variability is often explained by supply factors and the autocorrelation by the activities of speculators we show that this explanation is not consistent with the evidence speculation can substantially increase autocorrelation for prices that are weakly autocorrelated in its absence but not to the high levels that are observed in the data

unspanned stochastic volatility in affine models evidence from eurodollar futures and options unspanned stochastic volatility usv refers to the inability of bonds to replicate volatility sensitive derivative securities affine term structure models require special restrictions on the parameters to exhibit usv we use a joint eurodollar futures and options data set to estimate affine three factor models with and without usv restrictions the unrestricted model captures prices of futures and options well option pricing errors are much larger in the usv model the usv model is rejected in favor of the unrestricted model based on the likelihood ratio and wald tests we use the implications of the unrestricted model as a benchmark for understanding the extant evidence that favors usv specifically we replicate extant tests in samples simulated from the unrestricted model we show that none of the existing findings contradict the model without usv restrictions

the long term structure of commodity futures futures markets on agricultural commodities typically trade with maximum maturity dates of less than four years if these markets did trade with maturities eight or ten years distant futures prices would have value as price forecasts and as a way to structure long term swaps and insurance contracts agricultural commodity markets generally exhibit mean reversion in spot prices and convenience yields spot markets also exhibit seasonality this study develops and implements a procedure to generate long term futures curves from existing futures prices data on lean hogs and soybeans are used to show that the method provides plausible results copyright 2012 oxford university press

stochastic risk premiums stochastic skewness in currency options and stochastic discount factors in international economies abstract we develop models of stochastic discount factors in international economies that produce stochastic risk premiums and stochastic skewness in currency options we estimate the models using time series returns and option prices on three currency pairs that form a triangular relation estimation shows that the average risk premium in japan is larger than that in the us or the uk the global risk premium is more persistent and volatile than the country specific risk premiums and investors respond differently to different shocks we also identify high frequency jumps in each economy but find that only downside jumps are priced finally our analysis shows that the risk premiums are economically compatible with movements in stock and bond market fundamentals

schooling health knowledge and obesity the connection between schooling and health is well documented an important empirical issue that needs to be examined however is whether schooling s effects are due to individual health knowledge differences this empirical study examines this issue with an increasingly important health indicator obesity since provision of health knowledge is a major tool of public agencies promoting health this empirical study uses a new direct measure of health knowledge to test this hypothesis the results show that knowledge is inversely related to the probability that an individual is obese schooling s effects on relative weight and the probability of being obese are explained by differences in knowledge this result may imply that schooling s effect on the allocative efficiency of the household production of health is the main reason schooling is linked to health behaviour the result also may imply that the most effective method of health education is to highlight the disease element of poor dietary habits a

on the brazilian fuel pricing policy a gaussian factor model approach in this paper we investigate the oil spot price dynamics and volatility in brazilian reais the local currency the current policy on price adjustments of refined products caused enormous turmoil

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an exogeneity test for a simultaneous equation tobit model with an application to labor supply a test of weak exogeneity in the simultaneous equation tobit model is proposed and illustrated using a female labour supply model estimated using cross section data the test statistic can be simply output from any standard tobit maximum likelihood package and is asymptotically efficient the procedure provides consistent estimators for the simultaneous tobit model whose asymptotic covariance matrix is a simple extension of the usual tobit formula we also provide the lagrange multiplier test of weak exogeneity this abstract was borrowed from another version of this item