Mutualization in cybersecurity refers to the regulatory principle allowing multiple operators or service providers to share the same physical network infrastructure. This approach promotes efficient resource utilization, reduces costs, and encourages competition by preventing the duplication of expensive network assets. Mutualization is particularly relevant in sectors like telecommunications, where building separate infrastructures for each operator would be impractical and costly. By sharing infrastructure, operators can focus on providing differentiated services while ensuring network security and compliance with regulatory standards. Mutualization also supports faster deployment of new technologies and wider coverage, benefiting end-users and the overall digital ecosystem.