Stock Transport Order Stock Transport Process A stock transport order (STO) is a form of purchase order where a material is ordered from another plant instead of an external vendor. There is a requirement in the ordering plant and there is a replenishment in the supplying plant. These will need to be matched to each other. Typically, this type of stock transfer between two plants involves stock management (Using SAP EWM in case of EWM managed Warehouse) and purchasing in the