In an actuarial or financial context it is often necessary to calculate the distribution function or risk measures for random variables of the type
where the marginal distributions of the
X
i
are known but their dependence structure is too difficult to work with. Comonotonicity, which is an extremal form of positive dependence, can be useful to determine easily computable and accurate upper and lower bounds for the distribution of
S
, and hence also for risk measures related to
S
.