• We are pleased to announce that the winner of our Feedback Prize Draw for the Winter 2024-25 session and winning £150 of gift vouchers is Zhao Liang Tay. Congratulations to Zhao Liang. If you fancy winning £150 worth of gift vouchers (from a major UK store) for the Summer 2025 exam sitting for just a few minutes of your time throughout the session, please see our website at https://www.acted.co.uk/further-info.html?pat=feedback#feedback-prize for more information on how you can make sure your name is included in the draw at the end of the session.
  • Please be advised that the SP1, SP5 and SP7 X1 deadline is the 14th July and not the 17th June as first stated. Please accept out apologies for any confusion caused.

Copulas: October 2013 Q8

C

chriswragg

Member
In the question mentioned above, when using the probabilities of default in the copula functions, the answers substitute 0.05 and 0.15. In doing this, I presume we then looking at the joint distribution in the lower tail? Is there a reason why we would use this instead of 0.95 and 0.85 (and then manipulating in terms of a survival copula to answer the question
) and look at the upper tail? Does the choice of upper tail or lower tail just depend on whether we are thinking of positive or negative losses?

In the second part of the question the answers say a Gumbel copula may be most appropriate because of the upper tail dependence in the case of recession (ie as they are both more likely to default simultaneously). This seems contradictory to the first part, where it looks to me that if we are treating the defaults to be in the lower tail, a Clayton would be more appropriate.

Am I missing something here? Thanks!
 
Back
Top