Overstock, excessive stock, excess2sell, B-stock, or excess inventory, is the result of poor management of stock demand or of material flow in process management. Excessive stock is also associated with loss of revenue owing to additional capital bound with the purchase or simply storage space taken. Excessive stock can result from over delivery from a supplier or from poor ordering and management of stock by a buyer for the stock.

When referring to overstock merchandise in the form of consumer goods in a retail operation, the term refers to goods that have never been purchased by a customer but that are considered excessive stock from shelves and/or warehouses. Excessive stock is typically discarded of in the following ways: returned to the manufacturer or original distributor; liquidated to companies that then resell it on the secondary wholesale or retail market; sold at an extreme discount to existing customers; or sold to salvage companies which then process metals and components of value.