Buyer–supplier learning under uncertainty: relational mechanisms in big science innovation procurement

Abstract This article examines how ambidextrous relational capital can be developed and utilised within Big Science buyer–supplier collaborations to foster inter-organisational learning agility. Focusing on the high-uncertainty context of fusion energy research, the study employs qualitative, multiple-case research with leading Big Science Organisations, intermediaries, and SME suppliers across Europe. Through in-depth interviews and grounded theory analysis, three key dimensions are identified: relational foundations (trust, psychological safety, open communication), collaborative learning and adaptation (joint problem-solving, knowledge exchange, ambidextrous innovation), and outcome realisation (mutual performance, resilience, continuous improvement). The findings show that high-quality, psychologically safe relationships enable productive learning behaviours, supporting both incremental and breakthrough innovation. Addressing the exploration-exploitation tension and the governance of learning routines is central to sustaining ambidexterity. The study advances theory and practice by clarifying the micro-level mechanisms through which relational capital translates into inter-organisational learning capabilities for innovation in complex, multi-actor ecosystems.