Companies spend billions of dollars each year measuring and managing metrics like customer satisfaction and Net Promoter Score (NPS) to improve customer loyalty. Unfortunately, these metrics don't link to what matters most: share of wallet (i.e., the share of spending in a category that customers give to a brand). The Wallet Allocation Rule presents a revolutionary approach for winning the battle for share of customers' hearts, minds, and wallets. Backed by rock-solid science published in the Harvard Business Review and MIT Sloan Management Review The Wallet Allocation Rule provides managers with a definitive way to drive beyond traditional customer satisfaction and NPS to achieve goals for profitability, market share, and growth.