Turnover has a number of different, but related, meanings depending on the context in which it is used. Generally, it means the number of times an item is replaced with a new or similar version of that item.In the investment world, turnover refers to the number of securities traded as a percentage of the total, during a set period. This turnover ratio can refer to a portfolio of marketable securities, or the securities of an entire exchange. In brokerage accounts, high turnover is often bad because it could mean the broker is “churning” the account by generating unnecessary trades just to earn commissions. In accounting, turnover is used for a number of different ratios, particularly accounts receivable or inventory. Inventory turnover is calculated by dividing cost of goods sold by the average inventory for the period being measured. For this ratio, the higher the turnover the better, because it means goods are not sitting idle on shelves, but rather being used in production or sold in stores. In human resources, employee turnover is expressed as a percentage, and is calculated as the number of employees who left during a given period divided by the average number of employees during that same period. Multiply that quotient by 100 to get a percentage. High employee turnover is considered bad because of the high costs associated with constantly having to replace employees. High employee turnover also indicates low employee morale.