The component of gross private domestic investment that measures the change in the physical volume of inventories—additions less withdrawals—owned by private business, valued in average prices ofthe period. Inventories may be in the form of goods ready for sale (finished goods), of goods undergoing production (work in process), or of goods acquired for use in the production process (materials and supplies). CIPI differs from the change in the book value of inventories reported by most businesses, which are valued using a variety of accounting methodsand thus may include holding gains or losses resulting from price changes.