There are numerous social innovation networks and initiatives worldwide with the ambition to contribute to transformative change towards more sustainable, resilient and just societies. Many of these have a specific vision on the economy and relate to alternative visions of a ‘New Economy’. This paper highlights four prominent strands of new economy thinking in state-of-the-art discussions: degrowth, collaborative economy, solidarity economy, and social entrepreneurship. Taking a perspective of transformative social innovation, the paper draws on case studies of 12 social innovation initiatives to analyse how these relate to new economies and to transitions toward new economic arrangements. The 12 cases are analysed in terms of a) how they relate to narratives of change on new economies, b) how they renew social relations, and c) how their new economy arrangements hold potential to challenge established institutional constellations in the existing economy