Processus de Lévy en Finance - Laboratoire de Probabilités et ...
Processus de Lévy en Finance - Laboratoire de Probabilités et ...
Processus de Lévy en Finance - Laboratoire de Probabilités et ...
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Chapter 5<br />
Applications of Lévy copulas<br />
To apply Lévy copulas to multidim<strong>en</strong>sional financial problems with <strong>de</strong>p<strong>en</strong><strong>de</strong>nce b<strong>et</strong>we<strong>en</strong> ass<strong>et</strong>s,<br />
three kinds of tools are required:<br />
1. Param<strong>et</strong>ric families of Lévy copulas. Parsimonious mo<strong>de</strong>ls are nee<strong>de</strong>d because one typically<br />
does not have <strong>en</strong>ough information about the <strong>de</strong>p<strong>en</strong><strong>de</strong>nce to estimate many param<strong>et</strong>ers<br />
or proceed with a non-param<strong>et</strong>ric approach.<br />
2. Algorithms allowing to compute various quantities within a Lévy copula mo<strong>de</strong>l (e.g.,<br />
option prices, risk measures <strong>et</strong>c.)<br />
3. Estimation m<strong>et</strong>hods for Lévy copula mo<strong>de</strong>ls.<br />
In this chapter we give an answer to the first two questions. Section 5.1 <strong>de</strong>scribes several<br />
m<strong>et</strong>hods to construct param<strong>et</strong>ric families of Lévy copulas and gives examples of such families. In<br />
Section 5.2 we show how Lévy copulas can be used to simulate multidim<strong>en</strong>sional Lévy processes<br />
with <strong>de</strong>p<strong>en</strong><strong>de</strong>nce b<strong>et</strong>we<strong>en</strong> compon<strong>en</strong>ts. This simulation algorithm <strong>en</strong>ables us to compute the<br />
quantities of interest using the Monte Carlo m<strong>et</strong>hod. Estimation m<strong>et</strong>hods for Lévy copulas are<br />
the topic of our curr<strong>en</strong>t research and we do not discuss them here.<br />
A fundam<strong>en</strong>tal advantage of the Lévy copula approach compared to ordinary copulas is the<br />
possibility to work with several time scales at the same time. Wh<strong>en</strong> the time scale is fixed,<br />
the <strong>de</strong>p<strong>en</strong><strong>de</strong>nce structure of r<strong>et</strong>urns can be <strong>de</strong>scribed with an ordinary copula. However, on a<br />
differ<strong>en</strong>t time scale the copula will not be the same (cf. Example 4.1). On the other hand, a<br />
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