Medicare

Medigap

Private Medicare supplement insurance that fills gaps in Original Medicare's coverage.

Last reviewed: May 2026 · Editorial methodology

Definition

Medicare supplement insurance sold by private companies to help cover costs that Original Medicare (Parts A and B) does not pay, including copays, coinsurance, and deductibles. Plans are standardized and labeled A through N. Also known as Medicare Supplement Insurance. Plan G is the most comprehensive option available to new enrollees (Plan F is closed to anyone who became Medicare-eligible after January 1, 2020). The one-time Medigap open enrollment period starts the month you are both 65+ and enrolled in Part B.

Where this term matters

Medicare →

Tip

Glossary definitions are educational. Always check your own policy language — insurers can define common terms differently from one another. When in doubt, request a written explanation from your agent.

Related terms

Guaranteed IssueA policy that insurers must offer regardless of health status — no medical underwriting.IRMAA (Income-Related Monthly Adjustment Amount)IRMAA requires higher-income Medicare beneficiaries to pay surcharges on top of standard Part B and Part D premiums, with the amount based on income reported two years earlier.

Related guides

Source: Cover Forge USA editorial team|Last verified: May 2026|Methodology
Definitions are educational and may be simplified. Always refer to your policy contract and consult a licensed agent for terms that affect coverage decisions.
CF

Cover Forge USA Editorial Team

Editorial Lead

This article was researched and written by the Cover Forge USA editorial team against federal sources (NAIC, CMS, FEMA, DOL, SSA, state DOIs) and standard policy forms. Bylines organize content by topic — they do not assert individual licensure. See our editorial-policy for details.

Reviewed June 2026

Get Insurance Updates

Occasional updates on insurance rules, coverage changes and new guides — and ways to save.

  • ✓State-specific insurance rule changes
  • ✓Seasonal enrollment deadline reminders
  • ✓Expert tips to lower your premiums
  • ✓New coverage options in your state

Free forever. Unsubscribe with one click. No spam, ever.

Important Disclaimer

This site provides general educational information only and is not a substitute for professional insurance advice. All rates, data, and coverage details are estimates and may not reflect your actual premiums. Insurance availability and pricing vary by state, insurer, and individual risk factors. Always consult a licensed insurance professional in your state before making coverage decisions.

← Back to Insurance Glossary (355 terms)