The item category of a material determines how it is to be procured. Item category L (stock) tells the system to perform material requirements planning (MRP). For more information on requirements planning, see the Requirements Planning (PP-MRP) component.

As soon as the reservation is activated, the systems carries out an availability check for the material in the next MRP run. If there is not enough material in stock to meet the requirements, the system creates a planned order . Planned orders can be converted into production orders for the actual manufacture of the material component required or into purchase orders.

The item category and settings in the material master determine the type of stock in which the material can be kept as well as its account assignment category. If the material could potentially be kept in several types of stock , the system will ask you to choose the stock. For more information, see Material Component Inventory Management.