(6)The provision of ICT services to financial entities may rely on potentially long or complex chains of subcontracting which should be monitored by the financial entities. Financial entities should assess the associated risks, including ICT third-party concentration risks with regard to the ICT third-party service providers supporting a critical or important function or material parts thereof, considering a risk-based approach and the principle of proportionality. To enable that assessment, financial entities should be required to record in the register of information only those subcontractors that effectively underpin ICT services supporting critical or important functions or material parts thereof, including all the subcontractors providing ICT services whose disruption would impair the security or the continuity of the service provision. When identifying those subcontractors, financial entities should consider business and ICT service continuity and ICT security aspects.