Optimistic or negative unintentional inventory investment occurs when customers purchase a different amount with the firm’s product compared to firm expected within a particular time interval. Inventory investment is often a component of uncouth domestic product. Precisely what is produced in a specific country is obviously also sold sooner or later, but some with the goods produced inside a given year may be sold in a new later year in lieu of in the year they were holding produced. In short, Inventory investment = production – sales.