Elsevier

Energy Economics

Volume 25, Issue 3, May 2003, Pages 239-253
Energy Economics

Estimating oil price ‘Value at Risk’ using the historical simulation approach

https://doi.org/10.1016/S0140-9883(02)00111-1Get rights and content

Abstract

In this paper we propose using Value at Risk (VaR) for oil price risk quantification. VaR provides an estimation for the maximum oil price change associated with a likelihood level, and can be used for designing risk management strategies. We analyse three VaR calculation methods: the historical simulation standard approach, the historical simulation with ARMA forecasts (HSAF) approach, developed in this paper, and the variance–covariance method based on autoregressive conditional heteroskedasticity models forecasts. The results obtained indicate that HSAF methodology provides a flexible VaR quantification, which fits the continuous oil price movements well and provides an efficient risk quantification.

Introduction

Since the end of the nineteenth century, oil has been the main source of energy for mankind, and is the most widely used natural resource in energy production. Furthermore, movements in oil markets affect supply and demand of the other energetic commodities and incentive or disincentive research on alternative sources of energy. The strategic role of oil in our society became evident in the crisis of the seventies (1973 and 1979), and once again in the year 2000. Crude oil and refined products prices are not only relevant to oil market agents but also to governments and society. As Sadorsky (1999) suggests, changes in oil prices have an impact on economic activity, but changes in economic activity have little impact on oil prices. He states that oil price volatility shocks have asymmetric effects on the economy and finds evidence of the importance of oil price movements when explaining movements in stock returns. In the same way, Faff and Brailsford (1999) also find significant evidence of oil price sensitivity across some equity returns of Australian industry, using an augmented market model.

The agreements that OPEC members reached in the seventies and the reaction that those agreements caused in the oil market agents changed the controlled environment that had characterised the oil market up to then. The new market is relatively free and characterised by high price shifts. An unpredictable, volatile and risky environment has arisen and protection against market risk has become an essential issue.1

This volatile oil price environment requires a risk quantification. Value at Risk (VaR) has become an essential tool within financial markets when quantifying portfolio market risk (the risk associated with price movements). VaR determines the maximum loss a portfolio can generate over a certain holding period, with a pre-determined likelihood level. Therefore, VaR can be used, for instance, to evaluate portfolio managers’ performance by providing a risk quantification, expressed in monetary units (m.u.), which can be used, together with portfolio return (also expressed in m.u.), to this end. Moreover, it helps portfolio managers to determine the most suitable risk management policy for any given situation.

Within oil markets, VaR can be used to quantify the maximum oil price change associated with a likelihood level. This quantification is fundamental when designing risk management strategies.

This study proposes to quantify oil price VaR through the historical simulation (HS) approach. We develop a HS methodology (the historical simulation with ARMA forecasts approach, or HSAF), which, as we demonstrate, improves the VaR estimations provided by the HS standard approach. Furthermore, HSAF VaR estimations are more efficient than those provided by an autoregressive conditional heteroskedasticity (ARCH) model.

The rest of the paper is set out as follows: Section 2 introduces the VaR calculation procedure, and analyses the main methodologies and models that can be used to determine VaR. In Section 3 we put forward the fundamentals of the proposed methodology. Section 4 presents the empirical analysis: we estimate oil price VaR using the HS standard scheme, the proposed HSAF methodology and the ARCH models approach. The final section of the paper summarises the main conclusions of our study.

Section snippets

VaR calculation procedure

Within the area of finance, VaR can be defined as ‘an estimate of the largest loss that a portfolio is likely to suffer during all but truly exceptional periods. More precisely, the VaR is the maximum loss that an institution can be confident it would lose (in) a certain fraction of time over a particular period’.2 Thus, VaR sums up the risk which a portfolio or, in general, an entity is exposed to in just one figure: the amount which could be lost during an established holding

The historical simulation with ARMA forecasts methodology

The HSAF methodology, introduced and developed in this paper, belongs to the HS approach. However, HSAF methodology does not directly use the distribution of past returns, but rather the distribution of forecasting errors, derived from an estimated ARMA model. HSAF methodology implementation requires a four-stage procedure.

Stage 1: Past portfolio returns: HSAF methodology uses the autocorrelation property observed in most financial and economic data series when they are taken in absolute value

Data

We used daily spot Brent oil prices, from January 1992 to December 1999, and divided this time period into two smaller time periods:

  • The first, from 1992 to 1998, was used to estimate the model coefficients; this is the ‘in the sample period’.

  • The second, the year 1999, was used for forecasting purposes; this is the ‘out of the sample period’.

Fig. 1 shows oil price trends corresponding to the analysed period.

Historical simulation standard approach

Within the oil price environment, the HS standard approach assumes that price change

Concluding remarks

The volatile oil price environment requires a risk quantification. VaR has become an essential tool for this end when quantifying market risk (risk associated with price changes). Within oil markets, VaR can be used to quantify the maximum oil price change associated with a likelihood level. This quantification constitutes a fundamental point when designing risk management strategies.

There are several methods used to estimate oil price VaR. In this paper we analyse three of these methods: the

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