The companies participating in the CSI have all signed the CSI Charter . It summarizes the individual member actions included in the Agenda for Action, published in 2002. All companies joining the Initiative agree to implement these actions as a minimum requirement of membership, as part of their contribution to sustainable development. The CSI secretariat manages the process and ensures that companies are aware of and fulfill their various commitments.

The Charter was updated in 2009 and will be renewed as necessary to address developing issues. Since the document was issued in 2002, CSI members have further agreed to begin independent third party assurance of a number of the key performance indicators (KPIs), which are publicly reported. Beginning with 2006, companies carry out assurance of their CO2 data at least once every two years. They have also committed to independent assurance of their safety data, beginning with data from 2008. Other KPIs will be added over time.

Not all CSI member companies joined the initiative at the same time. Companies have four years from joining to meet the requirements of the CSI laid out in the CSI Charter. The below table gives the year when individual companies must start their public reporting: