We formulate the insurance risk process in a general Levy process setting,
and give general theorems for the ruin probability and the asymptotic
distribution of the overshoot of the process above a high level, when the
process drifts to -\infty a.s. and the positive tail of the Levy measure, or of
the ladder height measure, is subexponential or, more generally, convolution
equivalent. Results of Asmussen and Kluppelberg [Stochastic Process. Appl. 64
(1996) 103-125] and Bertoin and Doney [Adv. in Appl. Probab. 28 (1996) 207-226]
for ruin probabilities and the overshoot in random walk and compound Poisson
models are shown to have analogues in the general setup. The identities we
derive open the way to further investigation of general renewal-type properties
of Levy processes.Comment: Published at http://dx.doi.org/10.1214/105051604000000927 in the
Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute
of Mathematical Statistics (http://www.imstat.org