Medigap, a type of Medicare supplement insurance, assists in covering cost-sharing requirements under Medicare Part A and Part B, such as deductibles, copayments, and coinsurance. Offered by private insurers, these policies provide essential additional coverage for individuals on traditional Medicare who lack employer-sponsored retiree benefits or Medicaid. As of 2024, 12.9 million Medicare beneficiaries, representing 46% of all those on traditional Medicare, held a Medigap policy. Federal and state regulations govern Medigap issuance, including rules on medical underwriting, though guaranteed issue protections are typically limited in duration and do not apply equally across all age groups.
Federal Guarantees and Limits
The federal government sets specific windows where Medicare recipients can sign up for Medigap plans without facing health-based denials or higher costs. This includes the first half-year after enrolling in Medicare Part B and during certain qualifying scenarios, like when a Medicare Advantage plan ends coverage in their region or during the trial period for Medicare Advantage. Outside these protected periods, insurers are allowed to use medical underwriting to reject applicants or charge extra based on health history. For instance, someone with a pre-existing condition who switches from Medicare Advantage to traditional Medicare after the initial 12-month trial period—or who tries to buy Medigap outside the six-month enrollment window—could be turned down for coverage.
State Laws Offer Broader Protections
Individual states can implement additional protections beyond federal standards, such as offering ongoing or yearly guaranteed issue rights, extending coverage windows for specific life events, or ensuring access for those under 65. Eight states provide particularly broad continuous or annual guaranteed issue rights. Four states, Connecticut, Massachusetts, Maine, and New York, require these protections for all beneficiaries aged 65 and up, regardless of medical history.
Another four states, Delaware, Illinois, Minnesota, and Rhode Island, have expanded these rights, though their policies are less full. Rhode Island passed a law in 2025 allowing annual guaranteed issue rights for Medicare Advantage enrollees aged 65+, enabling them to buy Medigap. Minnesota’s rules, effective August 1, 2026, extend these protections to individuals aged 65 to 70.
Thirty-seven states require Medigap insurers to issue policies to Medicare beneficiaries ages 65 and older due to certain qualifying events, such as when an applicant has a change in their employer retiree coverage or when beneficiaries lose their Medicaid eligibility. Thirty-eight states require insurance companies to offer at least one kind of Medigap policy to Medicare beneficiaries under age 65 with disabilities during an initial open enrollment period, regardless of medical conditions. When these beneficiaries turn age 65, federal law entitles them to the same six-month open enrollment period for Medigap that is available to new beneficiaries ages 65 and older.
Related Post: Medicare premiums and out-of-pocket costs keep rising
Medigap policies must meet federal standards, including a six-month enrollment window starting the month a beneficiary joins Medicare Part B for those 65 and older. There are 10 standardized Medigap plans available to newly eligible individuals, though three states, Massachusetts, Minnesota, and Wisconsin, have their own set of standardized options. Federal rules also include minimum medical loss ratio requirements, a six-month cap on waiting periods for pre-existing conditions (unless the applicant has at least six months of prior continuous coverage), and a ban on new policies covering the full Part B deductible, which means Plans C and F are no longer sold to those turning 65 after January 1, 2020.
The Guaranteed Issue Enrollment Period
The one-time, six-month guaranteed issue period is intended to mitigate potential selection issues in the Medigap market. Rather than waiting to incur high health care costs before purchasing a Medigap policy, beneficiaries must generally purchase a policy during the initial open enrollment period, or they risk not being able to purchase a Medigap policy later.
Pre-Existing Condition Protections and Denial Risks
Insurers can deny policies or charge higher premiums outside guaranteed issue periods. Federal law allows this for those with pre-existing conditions who switch plans outside specific windows. For example, beneficiaries with medical conditions may be denied coverage if they change from Medicare Advantage to traditional Medicare after the initial trial period or buy a policy later than six months after Medicare enrollment.
Birthday Rules Allow Annual Plan Switches
Beyond these rules, some states have ‘birthday rules’ allowing policyholders to switch Medigap plans annually to one with equal or lesser benefits, either with the same or a different insurer, around their birthday. Sixteen states enforce these rules, requiring insurers to permit switches within a set timeframe, usually between 30 and 63 days.
Medigap insurers can deny coverage based on pre-existing conditions, except under limited circumstances, such as during a guaranteed issue period. This means that beneficiaries with certain medical conditions may be denied a Medigap policy outside of a guaranteed issue period, which can limit their access to supplemental coverage. According to the report analysis, nearly three quarters of Medicare Advantage enrollees have a medical condition that could result in a denial for Medigap, highlighting the need for guaranteed issue protections.
