Negative Inventory Levels
Negative inventory levels can result from some inventory transactions. Only nonserialized products can have negative inventory levels. Inventory levels can acquire negative values in the following circumstances:
When the logical inventory does not match the physical inventory (when the product is on the shelf, but the Siebel database does not show that the product is available).
When reconciling transactions to or from an External Location. The External Location must have negative quantities so that it can receive inventory from an external source.