The population of elderly people and their need for wellbeing and healthcare services is rapidly growing. At the same time, the supply for these services is not increasing at the same pace due to increasing costs and shortage of trained personnel. Therefore, many organizations are developing modern wellbeing ICT-enabled devices to assist the elderly people to live at their homes independently as long as possible and enabling the care providers to work more effectively. However, isolated attempts have led to emergence of countless devices and services with proprietary service platforms which have made this domain more complex. While collective action between actors for developing common service platforms may solve the complexity and foster adoption of these services, the challenges of cooperation hinder many actors from joint attempts. In this paper, we study how and why inter-organizational cooperation emerges in the home-care domain. Specifically, we study the impact of heterogeneity of interests and resources on the likelihood of collective action among participants in the healthcare domain. We do so by conducting a single case study on a unique collaborative elderly-care platform development project in Finland. The case was critical as it had all the required conditions (i.e. collective action for a common platform development project in the healthcare domain) to test our propositions. The results present the importance of resource heterogeneity for the emergence of collective action, especially in a business ecosystem of small companies with limited capitals and technical resources. We also found that heterogeneity of interests is not really problematic when the project is in the development phase (R&D) and especially in the presence of selective incentives that motivate participation of companies.@en