(15)For the purposes of assessing the importance of the operations of CSDs in host Member States, the assessment criteria should consider the size of the core services provided by CSDs to users from host Member States, including to issuers, participants in securities settlement systems or other holders of securities accounts maintained by CSDs. Where the size of core services provided by CSDs to users from host Member States is sufficiently large, the operations of CSDs in such host Member States should be deemed to be of substantial importance for the functioning of the securities markets and the protection of investors given that any failures or deficiencies in the operations of such CSDs may affect the smooth functioning of securities markets and the protection of investors in the host Member States concerned. In order to ensure a comprehensive assessment, it is appropriate to apply assessment criteria which consider independently the size of each core service provided by CSDs to users from host Member States.