The SIM card is traditionally owned by the MNO (Mobile Network Operator). But this will change in the future.
With the appearance of embedded SIMs or eSIMs that can be operated globally, they now support multiple subscriptions. It can be remotely programmed for new subscriptions, transfers the SIM ownership from the MNO to the device user. The benefits for smartphones are clear - it's easier to initiate and manage subscriptions - but what about the Internet of Things (IoT)?