By using resources more circularly, individual resources users hope to contribute to a more eco-efficient and sustainable resource use. Whether resources are used sustainably is decided at the macro-level, raising the question if, as well as how, the efficient and circular use of resources at the micro-level adds up to their efficient and circular use on the macro-level. Currently, the link between the circular use of resources at micro- and macro-levels is under-theorized. The symbiotic relationship between individual resource users enables a reduction in the resource use at the macro-level. In this conceptual paper, we argue that an analogous link exists in finance where desirable investment return is linked to undesirable investment risk, and that via the generation of efficient portfolios, individual risks are at least partially diversified away. As our main contribution, we theorize the circular economy, both in its perfect and imperfect forms, using modern portfolio theory. Our theory identifies the drivers of circular resource use and shows under which conditions individual resource use contributes to the circular use of resources.

通过更循环地使用资源，个人资源用户希望为更加生态高效和可持续的资源利用做出贡献。资源是否可持续利用是在宏观层面决定的，这就提出了一个问题，即微观层面的资源高效循环利用是否以及如何与宏观层面的资源高效循环利用相结合。目前，微观和宏观层面的资源循环利用之间的联系还没有充分理论化。个体资源使用者之间的共生关系能够在宏观层面减少资源使用。在这篇概念性论文中，我们认为金融中存在一种类似的联系，即理想的投资回报与不良的投资风险相关联，并且通过生成有效的投资组合，个人风险至少被部分分散。作为我们的主要贡献，我们使用现代投资组合理论对完美和不完美形式的循环经济进行了理论化。我们的理论确定了循环资源使用的驱动因素，并显示了在何种条件下个人资源使用有助于资源的循环使用。