Abstract
Digital Platforms have unique ways to create value through the coordination of constitutive agents, for which they require an adequate design and governance. Complementors are a fundamental actor in this value creation process, and thus understanding how they are impacted by the platform transformation is of social importance. Previous research has explored the consequences of competition between platform owners and complementors and identified the key features that describe this relationship over time. However, we do not know enough about how platforms impact on complementor transformation, and how complementors' responses affect, in turn, platforms' decisions. Consequently, in this article we ask: How do platform firms' business design decisions impact complementors over time? How do complementors respond? And how do these complementors' responses impact the platform firm? To address this gap, this paper evaluates the evolution of the Amazon Marketplace with a focus on the consequences over its Third-Party Sellers (3PS). We use an inductive grounded approach based on semi-structured interviews to the different types of actors in the ecosystem and triangulated with additional primary and secondary data sources. Our findings suggest that there is an endogenous interaction between platform's design decisions and complementors' response through the shaping of the ecosystem's competitive environment. We also find evidence of a duality in design decisions (official and unofficial), creating "unwritten rules" of competition. Finally, these dynamics seem to be driving complementors' heterogeneity, as we find evidence of the emergence of a new type of complementor, so-called "aggregators".