Mentoring Moment: Understanding Share of Customer Data-driven firms often use the metric "share of customer" or "share of wallet" to capture the percentage of an individual's purchase of products in a brand category. This provides a more accurate evaluation of an individual customer than using "share of market." Share of customer/share of wallet captures the percentage of an individual's purchase of a product that is the same brand. For example, if a customer spends $500 a year on lattes every year, and $350 was spent on Starbucks lattes, Starbucks' share of customer for that consumer is 70%. 

What share of wallet does Dunkin' Donuts have for that same customer if he spends $100 each year on Dunkin' Donuts lattes?