The chapter will provide an original and innovative insight into sustainable finance by analysing social movements’ interaction with complex finance dynamics (CFDs) through elements of trustworthiness. In doing so, the paper will draw on data from an empirical qualitative study that traced the involvement of social movements in shaping three major legal CFDs, namely project finance, bond finance and pension finance on the sustainable finance market between 2015 and 2018. It will argue that social movements, who are, by tradition, in conflict with dominant paradigms, pose a perceptible competitive challenge to major stakeholders who shape the finance dynamics. Whilst the utilisation of the trustworthiness analytical framework proves useful in uncovering the conflict, it serves the main purpose of demonstrating the analytic competition between social movements and the major stakeholders. The author argues that social movements should take a more responsible stance towards sustainable finance and, logically, adopt a form of responsible principles that will govern their relationship with the major stakeholders shaping the CFDs. Further, the author drafts principles in this chapter and argues that, if adopted by social movements, these will improve their competitive advantage on the fast-paced sustainable finance market.