Abstract
In the framework of Andersen's risk model, a new asymptotic expression and upper bounds on probabilities of ruin after time t(u) ≫ and before time 0 < t(u) ≪ , as the initial risk reserve u increases to infinity, are suggested. This result complements the classical normal-type approximation for the probability of ruin within finite time and is designed as its large deviations counterpart. The main technical device of the paper (see Section 3), which is of independent interest, are the upper bounds and the asymptotic expressions for the probabilities of large deviations of the stopped random walks, developed under low moment conditions.