Abstract: A transaction ledger blockchain supporting multiple entities of a supply chain processing system is instantiated; in response to a change in a ledger block, an on-hand inventory for a given item identifier is determined based on a reported sales history and an inventory block including inventory metadata that describes a temporal snapshot of the on-hand inventory. A unit and cost allocation of the on-hand inventory is determined and a true acquisition cost for the given item identifier is determined. A special price agreement (SPA) cost is determined based on an SPA block that includes terms of an SPA and a rebate amount corresponding to the given item identifier is calculated based on the SPA cost and the true acquisition cost. A total rebate is determined, another inventory block is generated based on a revised inventory, and a rebate blockchain is updated based on the determined total rebate.