Overstock, excessive stock, or excess inventory arise when there is more than the "right quantity" of goods available for sale, or when "the potential sales value of excess stock, less the expected storage costs, does not match the salvage value". It arises as a 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. Excess or unnecessary inventory is listed as one of the seven wastes or "muda" in Taiichi Ohno's Toyota production system.