As waste treatment companies are pivotal for a shift towards the circular economy, more insight into their decision-making process is needed. This paper explores how waste treatment companies make decisions facing the circular economy by using a qualitative research approach (semi-structured interviews, workshop, focus group) with 10 companies and experts across the EU in a framework of four interrelated markets. We found that the circular economy will exacerbate competition across markets, which creates difficulties for both public and private waste treatment companies to make the shift towards the circular economy in a changing technology landscape. Furthermore, there are institutional contradictions that arise due to lagging support mechanisms, leaving waste treatment companies with significant uncertainties concerning their transfer to a circular economy. Therefore, waste treatment companies will require a regulatory framework that meets their needs across various markets.