From a simple idea to unite pension funds in their quest for responsible investment at its launch in April 2006, the United Nations supported Principles for Responsible Investment (PRI) have grown in just one decade into an initiative with more than 1,500 fee paying signatories. These signatories consist of asset owners (e.g. pension funds, charities), the asset managers that serve them and service providers to both groups. Jointly, the PRI’s signatories hold over $60 trillion in assets under management, which makes PRI into one of the more prevalent non-for-profit organisations worldwide. This paper undertakes an empirical investigation of the stakeholder relationships PRI and its asset owner signatories during five crucial years of PRI’s emergence: 2007-2011. Guided by stakeholder salience theory, we explore the factors that drive asset owners to subscribe to PRI. Using a variety of public data sources, we overcomes the limitation of self-reported data qualifying the findings of Majoch et al. (2016). We find that for asset owners the most salient factors are utilitarian power, societal and pragmatic legitimacy, management values, and coalition building though the relevance of individual factor is not static but evolves over time with PRI’s emergence.