Federal rules grant a single six-month Medigap enrollment period at 65, after which insurers in most states can reject applicants based on health history.
Americans turning 65 receive a one-time, six-month guaranteed-issue window to purchase Medigap insurance, which caps out-of-pocket costs under Traditional Medicare. This window begins upon enrolling in Medicare Part B, not at the 65th birthday, and never reopens after closing.
Outside this period, insurers in 46 states can deny coverage, charge higher premiums, or exclude pre-existing conditions. Only four states—New York, Connecticut, Massachusetts, and Maine—require year-round guaranteed issue, though protections do not transfer if policyholders relocate. About 42% of Traditional Medicare beneficiaries hold Medigap policies, rising to 80% among those without employer or Medicaid supplemental coverage.
Medigap policies cover the 20% coinsurance and other cost-sharing left uncapped by Original Medicare, making the enrollment window critical for financial protection.