Also known as: SIEM as a Service
A SIEM offered as an ongoing service by a third-party provider, rather than software an organization installs, tunes, and staffs itself.
Managed SIEM is security information and event management delivered as an ongoing service rather than self-hosted software. Instead of licensing a platform like Splunk and dedicating internal staff to configure log sources, tune alert rules, and review findings, an organization sends its log data to a provider who runs and monitors the SIEM on its behalf.
The usual trigger for evaluating Managed SIEM is realizing a self-run platform's licensing and staffing cost has outgrown the value the organization is actually getting from it, particularly common when the platform was sized for a bigger security team than the organization actually has.