Stay In Volume

The portion of a company’s unit volume, sold during a period, resulting from the retention of existing customers and customer volume. Stay In volume has three components: (1) the proportion of the customer relationship volume that remains the same as in the beginning of the period; (2) the proportion of volume which remains from customers which have decreased use during the period; and (3) the original proportion of volume from customers who have increased the proportion of their purchases from the company (abbreviation: SI).