The overall brand value depends on customers’ subjective evaluation beyond the objective brand valuation. Social media, a critical component in subjective evaluation, has led to a transformation in brand advertising strategies that require increased emphasis on social media marketing to strengthen the brand. However, little attention has been given to assess brand value attributed to social media marketing—a key strategic component that has high managerial consequence. The purpose of this study is to establish key drivers and measures of social media equity—an essential aspect of a brand’s value, particularly in the evolving landscape of social media brand management. Theoretically grounded in social influence theory and social capital theory, this study establishes psychological and social drivers of the retailer brand’s social media equity. The paper, therefore, accommodates roles of psychological-, social-, and strategic-level factors, which encompass an effective social media marketing strategy. This study offers implications that significantly advance the theoretical and managerial literature on social media brand management for the retail industry.