A note on the finite-time ruin probability of a renewal risk model with Brownian perturbation

In this note, we consider a renewal risk model with constant force of interest and Brownian perturbation. Assuming that the claim-size distribution function is from the subexponential class, we derive for the finite-time ruin probability a precise asymptotic expansion, which holds uniformly for any finite time horizon. Our result confirms the intuition that the asymptotic ruin probabilities of risk models with heavy-tailed claims are insensitive to the Brownian perturbation.