The transition to a circular sustainable economy requires new, circular, business models based on strategies for closing, slowing or narrowing resource flows. While companies are used to sell products based on their forward supply chains, they are now more and more aiming to increase their sustainability and embrace circular economy principles. This does however lead to many challenges, and firms struggle to change their existing linear business models to circular business models. At the same time, we see new start-ups emerge that build a circular business model from scratch and challenge incumbent industries.