Most Growable Customers. Those customers for whom the Strategic Value, that is the potential value of the customer, most exceeds the customer's current Actual Value. These are the customers who have the most growth potential -- growth that can be realized through cross selling; through keeping the customer for a longer period; or perhaps by changing a customer's behavior and getting them to operate in a way that costs the enterprise less money. Most Growable Customers are also known as second-tier customers (STCs).