It is commonly accepted that the performance of sustainable business models is determined by their value creation for stakeholders, primarily understood in aggregated macro-level social, ecological and economic terms. However, very few studies attempt to measure this value creation beyond qualitative evaluations of firms, and the ones that do, focus on measuring the output of the firm. Because these output-based and firm-based metrics do not measure the fulfilment of stakeholder needs, they can only approximate actual stakeholder value creation. This implies that the conceptualisation and operationalisation of value created with sustainable business models require further clarification. In response, this paper analyses the characteristics of value itself based on insights from marketing and stakeholder research and how this affects the understanding of a business model’s sustainability performance. Conceptual propositions for value-based performance assessment of sustainable business models are derived from the characteristics of subjectivity and heterogeneity, relationality and experientiality, idiosyncrasy, incommensurability, one-sidedness and non-linearity, situation-specificity and transience, and interdependence. The analysis suggest that the trinity of ecological, social and economic value needs to be reformed with a value concept based on stakeholder-specific need-fulfilment that allows actual assessment of stakeholder value creation. This assessment can only be conducted in collaboration with the stakeholders whose needs are being addressed.