Broadly speaking, loyal customers bring in far more profit than any other category. I Feel Done OverDuring a recent survey, Capital One Shopping found that increasing customer loyalty by just 5% can lead to profit increases ranging from 25% to 95%. The cherry on top is that loyal customers boost shareholder returns between 2 and 5 times over a 10-year period. Research shows that 73% of American consumers are loyal to at least one brand, and 68% claim brand loyalty. Tomatoes#24 My Quart Of Milk Only Had 3 Cups Of Milk In ItThe irony is that many managers and owners understand that customer loyalty is important.