A software system is provided for managing available to promise (ATP) and making promises to fulfill customer requests. The software system includes a plurality of generic product models (600) each representing a generic product. Each generic product model (600) specifies one component of a plurality of possible components. A plurality of specific product models (602) each represent a specific product and each specify all components of the specific product. Each component specified by each specific product model (602) is specified by one of the generic product models (600) such that each specific product model (602) is related to a subset of the generic product models (600). A customer request matching a specific product then can be fulfilled by available-to-promise of the specific product or by available-to-promise of all related generic products. In addition, an organization in a seller hierarchy can retain product and designate first-come-first-served product. The organization also can define an ATP horizon to specify when forecasted product is actually available. Further, the organization can use an automatic allocation policy to allocate to members, and some forecast entries can be designated zero-ATP entries.