Optimal hedging in European electricity forward markets.

This article is concerned with modeling the dynamic and distributional properties of daily spot and forward electricity prices across European wholesale markets. Prices for forward contracts are extracted from a unique database from a major energy trader in Europe. Spot and forward returns are found to be highly non normally distributed. Alternative densities provide a better fit of data. In all cases, conditional heteroscedastic models are used with success to specify the data generating process of returns. We derive implications from the relation between spot and forward prices for the evaluation of hedging effectiveness of bilateral contracts. The relation is parametrized by the mean of multivariate GARCH models possibly allowing for dynamic conditional correlation. Because correlation between spot and forward returns is very low on each market, derived optimal hedge ratios are insignificant. We conclude to a great inefficiency for forward markets at least for short-term horizon. Hedging effectiveness is not improved, for our data, through the use of dynamic correlation models.Electricity; multivariate GARCH; dynamic correlation models; non Gaussian densities; optimal hedging; cross-hedging;

Revisiting the excess co-movements of commodity prices in a data-rich environment.

We reinvestigate the issue of excess comovements of commodity prices initially raised in Pindyck and Rotemberg (1990). While Pindyck and Rotemberg and following contributions consider this issue using an arbitrary set of control variables, we develop our analysis using recent development in large approximate factor models so that a richer information set can be considered. This ensures that fundamentals, a necessary concept for any excess comovement analysis, are modelled as well as possible. We then consider different measures of correlation to assess comovement and we provide evidence of excess comovement for a set of 8 seemingly unrelated commodities. Our results indicate that excess comovement in returns does exist even when the issue of heteroscedasticity is considered. We extend our analysis to the excess comovement of volatilities and show that, contrary to the case of returns, comovement vanishes once the effect of fundamentals have been taken out.spillover index; heteroscedasticity-corrected correlation; factor models; commodity excess comovement hypothesis;

Volatility transmission and volatility impulse response functions in European electricity forward markets.

A  l’aide de données quotidiennes  sur  la période mars  2001 à  juin  2005, nous estimons un modèle VAR‐BEKK  et montrons  l’existence  de  transmissions  au  niveau  des  rendements  et  des  volatilités  entre  les marchés  forward  de  l’électricité  pour  l’Allemagne,  les  Pays‐Bas  et  la  Grande‐Bretagne. Nous  appliquons  la fonction VIRF de Hafner and Herwartz [2006, Journal of  International Money and Finance 25, 719‐740] afin de mesurer  l’impact  d’un  choc  sur  la  volatilité  conditionnelle. Nous  observons  qu’un  choc  a  un  impact  positif important seulement si son amplitude est grande en regard du niveau de la volatilité à cet instant. Finalement, nous estimons  la densité des  fonctions VIRF pour différents horizons de prévisions.  Ces distributions lissées  sont asymétriques  et montrent que des  évènements extrêmes sont  possibles même si leur  probabilité est faible. Ces résultats ont des implications intéressantes pour les participants au marché dont la politique de gestion des risques est basée sur les prix des options, eux‐mêmes dépendant du niveau de volatilité.Using daily data from March 2001 to June 2005, we estimate a VAR-BEKK model and find evidence of return and volatility spillovers between the German, the Dutch and the British forward electricity markets. We apply Hafner and Herwartz [2006, Journal of International Money and Finance 25, 719–740] Volatility Impulse Response Function (VIRF) to quantify the impact of shock on expected conditional volatility. We observe that a shock has a high positive impact only if its size is large compared to the current level of volatility. The impact of shocks are usually not persistent, which may be a consequence of the non-storability of power. Finally, we estimate the density of the VIRF at different forecast horizons. These fitted distributions are asymmetric and show that large increases in expected conditional volatilities are possible even if their probability is low. These results have interesting implications for market participants whose risk management policy depends on option prices which themselves depend on the characteristics of volatility.volatility spillovers; electricity forward markets; multivariate GARCH; volatility impulse response function; transmission de volatilité; marché forward de l’électricité; GARCH multivarié; Fonction impulsion réponse de volatilité;

Options Introduction and Volatility in the EU ETS

To improve risk management in the European Union Emissions Trading Scheme (EU ETS), the European Climate Exchange (ECX) has introduced option instruments in October 2006 after regulatory authorization. The central question we address is: can we identify a potential destabilizing effect of the introduction of options on the underlying market (EU ETS futures)? Indeed, the literature on commodities futures suggest that the introduction of derivatives may either decrease (due to more market depth) or increase (due to more speculation) volatility. As the identification of these effects ultimately remains an empirical question, we use daily data from April 2005 to April 2008 to document volatility behavior in the EU ETS. By instrumenting various GARCH models, endogenous break tests, and rolling window estimations, our results overall suggest that the introduction of the option market had no effect on the volatility in the EU ETS. These finding are robust to other likely influences linked to energy and commodity markets.EU ETS, Option prices, Volatility, GARCH, Rolling Estimation, Endogenous Structural Break Detection

Options introduction and volatility in the EU ETS

To improve risk management in the European Union Emissions Trading Scheme (EU ETS), the European Climate Exchange (ECX) has introduced option instruments in October 2006 after regulatory authorization. The central question we address is: can we identify a potential destabilizing effect of the introduction of options on the underlying market (EU ETS futures)? Indeed, the literature on commodities futures suggest that the introduction of derivatives may either decrease (due to more market depth) or increase (due to more speculation) volatility. As the identification of these effects ultimately remains an empirical question, we use daily data from April 2005 to April 2008 to document volatility behavior in the EU ETS. By instrumenting various GARCH models, endogenous break tests, and rolling window estimations, our results overall suggest that the introduction of the option market had no effect on the volatility in the EU ETS. These finding are robust to other likely influences linked to energy and commodity markets.

Options introduction and volatility in the EU ETS

To improve risk management in the European Union Emissions Trading Scheme (EU ETS), the European Climate Exchange (ECX) has introduced option instruments in October 2006 after regulatory authorization. The central question we address is: can we identify a potential destabilizing effect of the introduction of options on the underlying market (EU ETS futures)? Indeed, the literature on commodities futures suggest that the introduction of derivatives may either decrease (due to more market depth) or increase (due to more speculation) volatility. As the identi¯cation of these effects ultimately remains an empirical question, we use daily data from April 2005 to April 2008 to document volatility behavior in the EU ETS. By instrumenting various GARCH models, endogenous break tests, and rolling window estimations, our results overall suggest that the introduction of the option market had no effect on the volatility in the EU ETS. These finding are robust to other likely influences linked to energy and commodity markets.EU ETS, Option prices, Volatility, GARCH, Rolling Estimation, Endogenous Structural Break Detection

Futures Trading and the Excess Co-movement of Commodity Prices

International audienceWe empirically reinvestigate the issue of the excess co-movement of commodity prices initially raised in Pindyck and Rotemberg (1990). Excess co-movement appears when commodity prices remain correlated even after adjusting for the impact of fundamentals. We use recent developments in large approximate factor models to consider a richer information set and adequately model these fundamentals. We consider a set of eight unrelated commodities along with 184 real and nominal macroeconomic variables, from developed and emerging economies, from which nine factors are extracted over the 1993–2013 period. Our estimates provide evidenceof time-varying excess co-movement which is particularly high after 2007. Wefurther show that speculative intensity is a driver of the estimated excess comovement, as speculative trading is both correlated across the commodity futures markets and correlated with the futures prices. Our results can be taken as direct evidence of the significant impact of financialization on commodity-price crossmoments

Impulse response to a shock of the correlation between three major stock indices : the Lehman Brothers bankruptcy

Notre objectif est de mesurer l’impact de chocs sur les corrélations conditionnelles de trois indices boursiers majeurs : le S&P 500, le FTSE 100 et le Nikkei 225. Nous estimons une version étendue du modèle à corrélations conditionnelles dynamiques avec effet d’asymétrie (ga-dcc) de Cappiello, Engle et Sheppard [2006] et procédons à une analyse impulsion-réponse en suivant l’approche de Koop, Pesaran et Potter [1996]. Nous étudions I’impact du choc en date du 14 août 2007 au moment du déclenchement de la crise de subprimes et de celui de la semaine du 16 septembre 2008, après la faillite de la banque Lehman Brothers. Nos estimations montrent que ces deux chocs ont eu des impacts nettement différents sur les trois corrélations.We proceed to an impulse-response analysis on the conditional correlations between three stock indices returns: the S&P 500, the ftse 100 and the Nikkei 225. As a first step, a general asymmetric dynamic conditional correlation (ga-dcc) model proposed by Cappiello, Engle and Sheppard [2006] is estimated. In a second step, we quantify the impact of two historical shocks on subsequent conditional correlations along the lines of Koop, Pesaran and Potter [1996]. The first chosen shock marks the beginning of the subprimes crisis and occurs on 08/14/2007. The second one corresponds to 09/16/2008, just after the bankruptcy of Lehman Brothers. Our estimates show that these two historical shocks had rather different impacts on conditional correlations.ou

Futures trading and the excess comovement of commodity prices

We empirically reinvestigate the issue of excess comovement of commodity prices initially raised in Pindyck and Rotemberg (1990) and show that excess comovement, when it exists, can be related to hedging and speculative pressure in commodity futures markets. Excess comovement appears when commodity prices remain correlated even after adjusting for the impact of common factors. While Pindyck and Rotemberg and following contributions examine this issue using a relevant but arbitrary set of control variables, we use recent developments in large approximate factor models so that a richer information set can be considered and “fundamentals” are likely to be adequately modeled. We consider a set of 8 unrelated commodities along with 187 real and nominal macroeconomic variables from which 9 factors are extracted over the period 1993-2010. Our estimates provide evidence of a time-varying excess comovement which is only occasionally significant, even after controlling for heteroscedasticity. Interestingly, excess comovement is mostly significant in recent years when a large increase in the trading of commodities is observed and also in crisis periods. However, we show that this increase in trading activity alone has no explanatory power for the excess comovement. Conversely, measures of hedging and speculative pressure explain around 60% of the estimated excess comovement thereby showing the strong impact not only of the financialization process, but also the impact of behaviour of somecategories of traders on the price of commodities and the fact that supply and demand variables are not the sole factors in determining equilibrium prices