Purpose The purpose of this paper is to study how digital business models evolve when entrepreneurs move to new digital platforms and how this evolution is related to effectuation and causation logics. Design/methodology/approach This study applies a multiple case study approach to investigate how digital business models change in small, Japanese high-tech firms providing their innovations through different digital platforms. To investigate digital business models, this study considers the elements that comprise general business models. The case firms were selected based on size, products and transitions from physical to various digital platforms. Semi-structured interviews were conducted with the key decision-makers from the case firms. Findings The findings show that through digital transformation, the case firms’ digital business models evolved by following effectuation logic as well as causal logic. All the firms employed causal logic when moving to new platforms, among other actions. The case firms used effectual logic with success for product development and adjustments to their network. Especially firms providing video games relied on effectuation for high impact products. Effectual logic did not play a role at all in changes to value delivery and had only little impact on revenue structures. Originality/value This research helps understand how digitalization of platforms and subsequent moves to newer digital platforms improve a firm by changing the business model elements through effectuation and causation logics. This research extends the understanding of digital business model transformation to a more granular level, business model elements.