We consider the joint cost allocation problem that arises when several
lots or resources are available to serve different products or divisi
ons. We provide a two-phase model, wherein the first phase the optimal
set of lots to be acquired is chosen and given the optimal set, and t
he products using each acquired lot is also determined. In the second
phase, a stable full cost allocation method is developed that will not
induce the divisions to form coalitions to reduce the allocated joint
costs. Utilizing the optimal dual solution of the lot selection phase
, we provide a joint cost allocation mechanism based on the concept of
propensity to contribute and show that this allocation is also stable
. If in the first phase there is a dual gap, then we show that there i
s no cost allocation in the core. A numerical illustration is provided
.