SAP MM cross-plant process guide
A stock transport order (STO) replenishes one plant from another plant through a purchasing document. It gives the receiving and supplying locations a shared requirement, a visible stock-in-transit flow and, where needed, delivery and intercompany billing documents.
What is a stock transport order in SAP MM?
An SAP MM stock transport order is a purchase order used by a receiving plant to request material from a supplying plant. The supplying source is another internal plant rather than an external supplier. The STO records the material, requested quantity, receiving plant, supplying plant, dates and delivery expectations, allowing both sides to plan and execute the transfer against the same reference.
A simple transfer posting can move stock, but an STO provides stronger process visibility. It can show open quantities, planned dates, goods issue, stock in transit, goods receipt and delivery history. Delivery-based variants also use shipping functions such as picking, packing and goods issue. Cross-company scenarios can add internal billing and invoice processing.
The STO should not be confused with ordinary external purchasing. Review the SAP MM purchase order guide for the shared PO concepts, then focus on the supplying-plant and receiving-plant relationship that makes stock transport different.
Intracompany versus intercompany stock transport orders
The key distinction is whether both plants belong to the same company code.
| Process question | Intracompany STO | Intercompany STO |
|---|---|---|
| Company-code relationship | Supplying and receiving plants belong to the same company code | Plants belong to different company codes |
| Commercial settlement | No intercompany customer/vendor billing between company codes | Can include internal billing by the supplying company and invoice receipt by the receiving company |
| Delivery processing | Optional, depending on the designed procedure | Common when shipping and billing are required |
| Accounting scope | Inventory moves within one legal entity | Inventory and intercompany receivable/payable effects span legal entities |
| Master-data dependency | Material and plant purchasing/shipping setup | Also requires the plant-linked customer, supplier and internal sales-area relationships |
Do not choose the process only by document convenience. The company-code assignment determines the legal and accounting relationship. A movement between two storage locations is not automatically an STO, and a cross-company movement cannot be treated as a simple internal quantity shift when billing and ownership transfer are required.
SAP MM stock transport order process
1. Create the requirement in the receiving plant
The receiving plant identifies a shortage or replenishment need. The requirement may originate from planning or be entered manually. The STO specifies the material, receiving plant, supplying plant, quantity and requested date. Availability is evaluated from the supplying plant’s perspective when the relevant checks are configured.
2. Create a replenishment delivery when required
In a delivery-based process, the supplying plant creates an outbound replenishment delivery with reference to the STO. The delivery provides warehouse and shipping teams with an execution document for picking, packing, staging and goods issue. Shipping point determination relies on supplying-plant and material/customer shipping data, so a missing result is often a master-data or assignment problem rather than an STO quantity problem.
3. Post goods issue at the supplying plant
Goods issue reduces the available stock of the supplying plant. In a two-step process, the quantity becomes stock in transit until the receiving plant posts receipt. This period matters operationally: the goods have left one location but have not yet been accepted by the destination. Teams should monitor aging transit quantities rather than treating goods issue as process completion.
4. Post goods receipt at the receiving plant
The receiving plant checks the delivery and posts goods receipt against the STO. The receipt increases stock at the destination and clears the corresponding in-transit quantity. The SAP MM goods receipt guide explains how receipt affects stock, material documents and PO history.
5. Complete intercompany billing where applicable
For a configured cross-company process, the supplying company creates the internal billing document and the receiving company records the corresponding invoice. The internal price, tax and account postings must agree with the organisations and master data. Billing is not an extra step to add to every STO; it belongs only to the appropriate intercompany design.
6. Reconcile open quantities and transit stock
Completion means more than a received delivery. Compare STO ordered quantity, delivered quantity, goods issue, goods receipt, returns, stock in transit and billing status. Short shipment, damage or reversal should remain visible through the original document chain.
One-step and two-step transfer
In a one-step transfer, issue and receipt are represented together, making it suitable only when the physical and control circumstances justify immediate destination receipt. In a two-step procedure, the supplying plant posts goods issue first and the receiving plant posts goods receipt later. The interim stock-in-transit position reflects the real gap between dispatch and receipt.
The two-step method provides clearer custody and timing evidence for transfers that travel between sites. It also creates a reconciliation responsibility: delayed receipts, partial receipts and reversals can leave old quantities in transit. A recurring report should assign each exception to the supplying location, carrier or receiving location based on the document history.
Master data and configuration prerequisites
- Material extension: the material needs the relevant purchasing, planning, accounting and, for delivery processing, shipping data in the participating plants.
- Plant relationship: the receiving and supplying plants must be correctly assigned to company codes and purchasing structures.
- STO document setup: document type, supplying plant, delivery type and checking rule must support the chosen process.
- Shipping data: delivery-based STOs need a determinable shipping point, sales area and required loading or transportation fields.
- Plant-linked business partners: intercompany flows need the supplying plant represented for the receiving purchasing organisation and the receiving plant represented for internal sales and shipping.
- Pricing and billing: cross-company processes require an agreed internal pricing and account-posting design.
For S/4HANA business-partner concepts, see the SAP MM Business Partner supplier master guide. In an intercompany STO, plant-linked customer and supplier roles are structural integration data, not merely address records.
STO troubleshooting checklist
| Symptom | Likely cause area | First evidence to inspect |
|---|---|---|
| No delivery can be created | Delivery type, shipping data, open quantity or date | STO item and schedule lines, supplying plant and delivery-due status |
| Shipping point is missing | Plant assignment, shipping condition or loading group | Supplying-plant material data and receiving-plant customer data |
| Goods issue posts but receipt cannot be made | Reference, receiving plant, stock type or open quantity | Material and delivery documents plus STO history |
| Stock remains in transit for too long | Unposted receipt, partial delivery, reversal or quantity difference | Transit report matched with physical shipment evidence |
| Intercompany billing is missing | Billing relevance, internal customer/supplier or pricing setup | Delivery document flow and billing due list |
| Receiving value differs from expectation | Valuation, internal price or account determination | Material valuation data and accounting documents |
Start with the STO history and document flow. Confirm which step actually completed before changing master data or configuration. For example, an open transit balance can be correct while a truck is en route; it becomes an exception when the physical receipt occurred but the system receipt did not.
Practice scenario
Plant A supplies 50 units to Plant B. Run an intracompany two-step STO with a replenishment delivery: create the order, confirm availability, pick and issue 50, receive 47 and record a three-unit shortage for investigation. Review stock in transit after each posting. Then outline how the master data, delivery type, billing document and accounting entries would change if Plant B belonged to another company code.
Compare the result with supplier consignment in SAP MM. An STO moves material from an internal supplying plant; consignment brings supplier-owned material into the buyer’s premises and delays liability until withdrawal. For the G/L logic behind inventory movements, continue with automatic account determination in SAP MM.
Frequently asked questions
What is the difference between a stock transfer and a stock transport order?
A stock transfer describes the movement of material between locations. An STO uses a purchasing order to plan, execute and track a transfer between plants, with options for delivery processing and intercompany billing.
What is stock in transit?
In a two-step transfer, stock in transit is the quantity issued by the supplying plant but not yet received by the destination. It provides visibility during the physical journey and must be reconciled when receipts are delayed or quantities differ.
Does every STO need an outbound delivery?
No. SAP supports STO procedures with and without delivery, depending on configuration and business requirements. Delivery-based processing is useful when warehouse and shipping execution needs picking, packing and dispatch documents.
When is intercompany billing used?
Intercompany billing is relevant when the supplying and receiving plants belong to different company codes and the designed process requires an internal commercial settlement between the legal entities.