In this paper, we discuss a common decision-making problem arising in the a
llocation and decentralization of resources under uncertain demand. The tot
al resource requirements for a given service level equals the sum of mean d
emands plus a safety factor multiplied by the standard deviations of demand
s. Since the demand means are unaffected by any customer groupings, we atte
mpt to exploit demand correlations for developing customer groups such that
the sum of the standard deviations over all groups is minimized. A concave
minimization model with binary variables is developed for this purpose and
a heuristic partitioning method is proposed to efficiently solve the model
. The model is appropriate for both manufacturing and service management wi
th potential applications in salesforce allocation, grouping of machines in
job shops, and allocation of plant capacities.