What counts as a qualifying life event for a Medicare Special Enrollment Period?

CMS defines qualifying life events for a Medicare Special Enrollment Period as specific changes in your circumstances outside standard enrollment dates — including moving to a new address outside your plan's service area, moving into or out of a nursing home or long-term care facility, losing creditable employer or union coverage, qualifying for or losing Medicaid or Extra Help, your plan leaving Medicare or changing its CMS contract, being affected by a FEMA-declared disaster or emergency, and other categories Medicare lists on the official SEP chart at Medicare.gov.