Guaranteed issue refers to health insurance coverage that is guaranteed to be issued to applicants regardless of their health status, age, or income.
Prior to 2014, individual market health insurance (the kind you buy on your own, rather than obtaining from an employer) was typically not guaranteed issue. Instead, insurers in most states based eligibility on an applicant's medical history. But that changed when the bulk of the Affordable Care Act's provisions were implemented in 2014.
All individual-market major medical plans in all states are now guaranteed issue, and applicants' medical history is no longer a factor in their eligibility. The trade-off is that enrollment is now limited to one annual open enrollment period, and special enrollment periods triggered by qualifying events (prior to 2014, people could apply for individual market coverage at any time, but eligibility in most states was contingent on medical history).
