Collective risk theory is concerned with random fluctuations of the to
tal net assets, the risk reserve, of an insurance company. In this pap
er we consider weak approximations in risk theory which are especially
relevant whenever the claim experience allows for heavy-tailed claims
. We approximate the risk process by an alpha-stable Levy motion (1 <
alpha < 2) with drift. The ruin probability within a finite time horiz
on is estimated. Finally, a numerical example is presented. (C) 1997 E
lsevier Science B.V.