Before revision:  The challenge in this setting, when no modelspecification for these securities nor for the death timeis given, lies in finding the dynamics and the structures for the mortality / longevity securities used in the securitization.
After revision:  The challenge in this setting, when no modelspecification for these securities nor for the death timeis given, lies in finding the dynamics and the structures for the mortality / or longevity securities which are vital for the insurance securitization.