Leptokurtosis: Difference between revisions

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Leptokurtosis is observed in many financial distributions. It means a more ‘pointy-headed’ and ‘fat tailed’ observed distribution, compared with the distributions predicted by the normal and lognormal models.  
Leptokurtosis is observed in many financial distributions.  
 
It means a more ‘pointy-headed’ and ‘fat tailed’ observed distribution, compared with the distributions predicted by the normal and lognormal models.
 
 
Importantly, there is a fatter downside tail (‘left tail’) in the observed data.
 
In other words the observed frequency of large negative returns (or results) is greater than predicted - for example - by the lognormal model of the distribution assumed in the Black Scholes option pricing model.


Importantly there is a fatter downside tail (‘left tail’) in the observed data. In other words the observed frequency of large negative returns (or results) is greater than predicted - for example - by the lognormal model of the distribution assumed in the Black Scholes option pricing model.


Because of leptokurtosis, Value at Risk models which use a normal frequency distribution will understate the Value at Risk.
Because of leptokurtosis, Value at Risk models which use a normal frequency distribution will understate the Value at Risk.


== See also ==
== See also ==
* [[Black Scholes option pricing model]]
* [[Black Scholes option pricing model]]
* [[Fat tail]]
* [[Leptokurtic frequency distribution]]
* [[Leptokurtic frequency distribution]]
* [[Lognormal frequency distribution]]
* [[Lognormal frequency distribution]]
* [[Normal frequency distribution]]
* [[Normal frequency distribution]]
* [[Tail]]
* [[Value at risk]]
* [[Value at risk]]


[[Category:The_business_context]]

Latest revision as of 17:36, 1 July 2022

Leptokurtosis is observed in many financial distributions.

It means a more ‘pointy-headed’ and ‘fat tailed’ observed distribution, compared with the distributions predicted by the normal and lognormal models.


Importantly, there is a fatter downside tail (‘left tail’) in the observed data.

In other words the observed frequency of large negative returns (or results) is greater than predicted - for example - by the lognormal model of the distribution assumed in the Black Scholes option pricing model.


Because of leptokurtosis, Value at Risk models which use a normal frequency distribution will understate the Value at Risk.


See also