This pioneering work explores the main barriers to digitization in small, family-owned retailers (i.e., nanostores), in emerging markets. Given their informal status, shopkeepers tend to stay “under the radar” and distrust any form of digitization because they are concerned that their transactional records might become transparent to the tax authorities, a phenomenon we term “tax privacy concerns”. To analyze the negative effect of tax privacy concerns, we applied three field studies where shopkeepers were exposed to smartphone apps designed to solve nanostores’ operational issues (e.g., sales records, order generation, and credit management). Based on these studies, we analyze shopkeepers’ willingness to digitize their operations. Overall, we integrate hundreds of responses across three cities, two in Mexico and one in Colombia. First, we analyze what entities shopkeepers are most willing to share data with, finding that their suppliers are their favorite alternative, followed by academia, with the least preferred being the government and startups. Second, we studied shopkeepers’ differential willingness to digitize if the system was offered either by the government, startups, or suppliers, finding that tax privacy concerns remain even when suppliers offer digital solutions. Yet, positive word-of-mouth, suggesting that data are unlikely to be shared with the tax authorities does mitigate tax privacy concerns. Overall, this study provides evidence for the existence and influence of privacy concerns beyond the consumer context. Such concerns are specific to shopkeepers’ operational data and relate to transparency of such data to the tax authorities. It also provides evidence for the likely success of potential mitigation strategies to address tax privacy concerns.