Like any other retailer, grocery stores want to build trust with their customers and keep them coming back. But the average bill and already slender margins in grocery can make it challenging to create a loyalty program that provides sufficiently compelling rewards. Nevertheless, it’s worth the effort, given that loyalty programs are a powerful incentive for grocery shoppers. In the US, for example, more than 60% of grocery store loyalty program members say that the financial incentives (such as discounts and promotions) influence where they shop and how much they spend. The first challenge is…