Maximum aggregate loss in a classical risk model (source code)

= Maximum aggregate loss in a classical risk model
{title2=$L=\sup_{t\geq0}(S(t)-ct),\quad\mathbb P(L>u)=\psi(u)$}

Starting from capital $u$, ruin occurs exactly when the aggregate loss exceeds $u$. Positive <relative safety loading> and the <strong law of large numbers> make $S(t)-ct$ tend to minus infinity, so its supremum is finite almost surely. For <exponential distribution> claims of rate $\alpha$, $L$ has an atom $1-\lambda/(\alpha c)$ at zero, and, conditional on $L>0$, has <exponential distribution> of rate $\alpha-\lambda/c$. The <ultimate ruin probability> determines this mixture directly.