SAP MM: Inventory Management and Movement Types in SAP
Olivia Turner
⚡ Smart Summary
Inventory Management in SAP MM tracks every goods movement through movement types, material documents, and stock types, driving receipts from purchase orders, transfers between plants, and issues for delivery in one unified module.
Inventory Management in SAP MM
Inventory Management is the SAP MM sub-module that tracks the physical stock of every material at every plant and storage location. It rests on four core processes: movement type maintenance, reservations, goods receipt, and goods issue.
Basic goods receipt was already covered in the purchase order topic, where a receipt is posted against an existing PO. Inventory Management extends that model to every kind of movement — PO receipts, production-order receipts, transfers between plants and storage locations, issues for delivery, and unplanned scrapping.
The most important transactions and functions are covered in the sections below.
What is Movement Type in SAP?
Movement Types are three-digit indicators of the purpose of a goods movement — for example, moving stock between storage locations, receiving stock from a purchase order, issuing stock for a delivery, or receiving finished goods from a production order.
The movement type classifies the posting, drives the account determination in Finance, controls which fields appear on the goods-movement screen, and decides whether the material document has a source location, a destination location, or both.
Movement types in SAP – Examples
Movement types ship with predefined settings in the standard SAP system and can be customised to match business needs. A movement type is a three-digit identification key for a goods movement such as 101, 201, 311, or 321.
The same movement type can serve different processes when combined with a movement indicator. For example, movement type 101 with indicator B is used for goods receipt against a purchase order, while movement type 101 with indicator F is used for goods receipt against a production order.
The next screen shows how the movement-type maintenance screen appears. Movement types are configured through transaction OMJJ.
- Execute the OMJJ transaction. On the initial screen, choose Movement type, then enter the movement-type range you want to edit.
- The screen that appears has a dialog structure on the left. These nodes drive the settings applied to each movement type.
- Selecting any node updates the detail screen on the right with the settings that belong to it.
Full OMJJ configuration falls outside the scope of this tutorial because it requires deep knowledge of the MM inventory-management processes. The important point for now is what the movement type and movement indicator represent.
Feel free to take a tour of the OMJJ transaction to see the settings available at both movement-type and movement-type/indicator level.
To summarise, movement types classify how goods flow through inventory. A few common examples:
- Movement type 101 — goods receipt.
- Movement type 311 — stock transfer from one storage location to another in one step.
- Movement type 601 — goods issue for an outbound delivery.
Every movement type has a paired reversal movement type. To cancel 311 the reversal is 312. Similarly, 101 reverses with 102, and 601 with 602.
A material document is the SAP document that records the processing of a goods movement (receipt, issue, or transfer). Creating a material document actually moves stock quantity in the way defined by the movement type.
If movement type 311 is set on the material document, the material is transferred from one storage location to another. If it is 101, the material document has no source location but does have a destination (receipt). If it is 601, the material document has only a source location and no destination (issue).
Types of Stock in SAP MM
Every stock quantity in SAP MM sits in a specific stock category. The category decides whether the quantity is available for planning, reserved for orders, or locked out of MRP. The main stock types are:
- Unrestricted-use stock — freely available, counted in MRP, and ready to consume or ship.
- Quality inspection (QI) stock — posted after receipt, not usable until a usage decision in QM releases it.
- Blocked stock — damaged or on-hold quantity that must not be consumed. Not counted in MRP.
- Stock in transit — issued from the sending plant, not yet received at the destination during a two-step transfer.
- Consignment stock — vendor-owned stock at the buyer’s premises. Ownership transfers only on withdrawal.
- Returns stock — goods returned by a customer, pending a decision to scrap, block, or return to unrestricted.
Reports MMBE (stock overview), MB52 (warehouse stock list), and MB5B (stock on posting date) show every stock type by material, plant, and storage location.
Common Inventory Management Transactions
Daily inventory work usually happens in a small set of transactions. The core list to know:
- MIGO — the unified goods-movement transaction. Handles receipt against PO, receipt against production order, transfer, and issue in one screen.
- MB1A — goods issue (movement types 201, 261, 551, 601, and reversals).
- MB1B — transfer posting between storage locations or plants (movement types 311, 313, 411, 412).
- MB1C — other goods receipt without reference (movement types 501, 561 initial stock upload).
- MB01 — goods receipt for a purchase order (legacy transaction; MIGO is the modern replacement).
- MB51 — material document list report filtered by movement type, date, plant, or material.
- MB52 — warehouse stock list by material and storage location.
- MMBE — stock overview by plant, storage location, and stock category.
- MB5B — stock on posting date, useful for period-end audit and balance verification.
Programmatic movements use BAPI BAPI_GOODSMVT_CREATE, which is the recommended route for external clients, LSMW loads, and RPA scripts that post stock movements.
Goods Receipt Scenarios
As covered earlier, a goods receipt can be posted with reference to a purchase order, a production order, an inbound delivery, or without any reference for other kinds of receipts.
Movement-type behaviour changes according to the movement indicator. Several indicators specify the reference-document type and, in combination with the movement type, drive posting behaviour:
- B — purchase order.
- F — production order.
- L — inbound delivery.
- Blank — no reference.
- Other — not significant for this introduction.
The combination of movement type and movement indicator classifies every goods receipt precisely and links the material document to the correct source document in the process chain.
