What is Medigap and how does it work with Original Medicare?

Quick Answer

Medigap is supplemental insurance sold by private companies that helps pay costs Original Medicare does not fully cover, like deductibles, coinsurance, and copayments. It works alongside Original Medicare, not instead of it.

Detailed Explanation

When you use Original Medicare, you typically share the cost of care. Part A has a deductible for hospital stays. Part B usually covers 80% of approved services, leaving you responsible for the other 20% with no annual cap. Medigap, also called Medicare Supplement insurance, is designed to pick up some or all of those leftover costs.Medigap plans are standardized by the federal government and labeled with letters, like Plan G or Plan N. Every insurer selling Plan G must offer the same core benefits. What varies between companies is the monthly premium, not the coverage itself. That standardization makes it easier to compare.To have Medigap, you need to be enrolled in Original Medicare Parts A and B. You cannot use a Medigap policy with a Medicare Advantage plan. The two approaches serve different needs and are not designed to stack.The best time to buy Medigap is during your six-month open enrollment window, which starts the month you turn 65 and are enrolled in Part B. During that window, insurers cannot deny you coverage or charge you more based on health conditions. Outside that window, you may face medical underwriting in most states, meaning your health history could affect whether you qualify or what you pay.Medigap does not include prescription drug coverage, so you would still need a separate Part D plan.

How This Applies in Utah

In Utah, Medigap plans are sold by carriers including Regence BlueCross, SelectHealth, UHC, Aetna, and others. Premiums for the same plan letter can vary significantly from one insurer to the next, so comparing quotes matters. The ADRC's SHIP counselors can help you review options at no charge.

What This Means For You

For you, this means Medigap trades a predictable monthly premium for more predictable out-of-pocket costs, which can be valuable if you see doctors often or want protection against a large unexpected medical bill.

Disclaimer

How Resting Sycamore Advisors Uses CMS Data

Our Commitment to Reliable Medicare Information

At Resting Sycamore Advisors, we work to provide accurate, current, and trustworthy information about Medicare Advantage, Medicare Part D, and Special Needs Plans.

To do that, we use data published by the Centers for Medicare & Medicaid Services (CMS), which is the official source for Medicare plan and enrollment information.

CMS Data Sources We Rely On

Our Medicare plan pages and comparison tools are powered by CMS datasets, including:

  • Medicare Advantage and Part D Landscape Files for annual plan availability and benefit details
  • Plan Benefits Package (PBP) Files for detailed benefit and coverage information
  • Part C and Part D Performance Data for quality ratings and plan performance measures
  • Monthly Enrollment Data for enrollment counts by contract, plan, state, and county

When possible, we link to the original CMS resources so you can review the source material directly.

How Often We Update Our Data

We follow the CMS release schedule and update our website as new data becomes available.

Annual Plan Year Updates (September)

We load new plan year Landscape and PBP files before the Medicare Annual Enrollment Period (October 15 through December 7). We also monitor CMS.gov for updates or revisions and refresh our content when needed.

Mid-Year Updates

We update enrollment and performance data as CMS publishes revised files, which are typically released monthly or quarterly.

Ongoing Maintenance

We routinely monitor CMS announcements for corrections, reissued files, or other changes and update our pages accordingly.

Each plan page includes a Last Accessed date so visitors can see when the source information was most recently reviewed.

How We Prepare CMS Data for Our Website

CMS data can be difficult to read in raw form. To make it easier to use, we format and organize the data for clarity.

This includes:

  • Standardizing plan identifiers such as contract ID, plan ID, and segment
  • Normalizing terminology so common Medicare terms are presented consistently
  • Organizing plan information by state, county, and ZIP code to match how people shop for coverage

All data values come from CMS. We do not change the underlying values beyond formatting, organization, and presentation.

Version Tracking and Transparency

We keep internal records of the CMS dataset versions used on our site.

Major Version History

  • Current Version: CY2025 Medicare Advantage and Part D Landscape Files (v1.0, published October 2025)
  • Prior Version: None. Resting Sycamore Advisors first began publishing structured Medicare plan information in March 2025

If CMS issues corrected or revised files, we update our website to reflect the latest available version.

Important Limitations

Please keep the following in mind:

  • CMS is the official source of truth. For enrollment and coverage decisions, always confirm details with Medicare.gov or 1-800-MEDICARE.
  • Data timing can vary. Enrollment and performance updates may appear on our website a few weeks after CMS publishes changes.
  • Plan details can change. Plan availability, costs, and benefits may change. Always verify current details directly with the plan provider.

Need Help From Official Medicare Resources?

For personalized Medicare assistance, please use these official resources:

  • Medicare.gov Help Center — https://www.medicare.gov
  • 1-800-MEDICARE (1-800-633-4227) TTY: 1-877-486-2048
  • State Health Insurance Assistance Program (SHIP) — free local counseling for Medicare beneficiariesIf you want, I can also give you a shorter legal-style version for a footer or /disclaimer page summary.