Literature on intermediation in transitions has emphasised the importance of publicly promoting intermediation. To understand what drives authorities to financially promote intermediation, we conducted an exploratory study of 16 Swedish municipalities promoting an intermediary actor in the mobility transition, applying the framework of drivers of collaborative governance. The results highlight drivers common to most municipalities, including among others administrators’ awareness of collaboration challenges, or their inability to conduct intermediary activities on their own. However, the results also reveal diversity and context dependency of the drivers, leading to municipalities voicing diverse and partly conflicting expectations towards the intermediary. These findings underline the importance of understanding the promotion of intermediation through municipalities as a transactional and personal relationship between administrators and intermediaries. They also underline the relevance of “affective work” to mitigating conflicts caused by the diversity of expectations facing intermediaries, and the importance of municipalities in shaping local ecologies of intermediation. © 2025 The Author(s)