The European Commission initiated a series of Directives and Regulations that aim to turn the linear economy into a climate-neutral and circular economy. Business-to-government information- sharing arrangements play an essential role in monitoring compliance with these regulatory measures. To this end data from the supply chain of products needs to be combined to create a full picture of the product life cycle. This requires the design of data-sharing arrangements in which businesses and governments share data. The EU proposal to introduce the Carbon Border Adjustment Mechanism (CBAM) obliges EU importers and non-EU exporters to buy carbon certificates for goods imported into the EU Customs Union. Upon implementation, the CBAM will require monitoring activities by the EU Custom Authorities. We use the case of the import of steel for the EU automotive industry to explore the required data, scenarios for (voluntary) data sharing, and the role of (future) digital infrastructures for e-government. Our analysis shows that data sharing for compliance with the CBAM Regulation is relatively simple. However, if Customs Authorities need to go beyond the monitoring of single regulations, the situation becomes more complex. In addition, the diversity of data sources owned by a network of actors in different (future) digital infrastructures will increase. Future research needs to go beyond data-sharing solutions for monitoring single regulations for circular economy towards combined data sharing for multiple regulations. This requires alignment between public and private interests to limit the administrative burden for businesses and government and an assessment of which digital infrastructures developed can be used to support data sharing. @en