This term is used within the GSMA’s Remote SIM Provisioning standard to describe the manufacturer of an eUICC (embedded Universal Integrated Circuit Cards) or embedded SIM. The eUICCs are sold to device manufacturers and mobile network operators (MNOs). EUMs are responsible for creating specifications and designs for eUICCs, which involve defining the hardware, software, and security features. They also manufacture the physical eUICC cards that include the embedded SIM functionality. Ensuring the security of eUICCs is crucial, so EUMs implement security measures such as encryption, authentication and secure storage.