What is Form CMS-L564 and what is it used for?

Quick Answer

Form CMS-L564 is a form your employer completes to confirm you had employer-sponsored group health coverage. You use it when enrolling in Medicare Part B outside your Initial Enrollment Period to avoid a late penalty.

Detailed Explanation

When most people turn 65, they have a limited window to sign up for Medicare Part B, the part that covers doctor visits and outpatient care. If you miss that window, you can face a permanent late enrollment penalty added to your premium.However, there is an exception. If you delayed Part B because you were covered by a group health plan through your own active employment or a spouse's active employment, you are entitled to a Special Enrollment Period. This lets you sign up for Part B without a penalty after that coverage ends.To use that Special Enrollment Period, Social Security needs proof that your delay was for a legitimate reason. That's where Form CMS-L564 comes in. Your employer fills out this form to confirm that you had employer-sponsored group health coverage and for what period. You submit it along with your Part B enrollment application, typically Form CMS-40B.A few things worth knowing: the coverage must be based on current, active employment, not retiree coverage or COBRA. Retiree insurance and COBRA do not qualify you for this exception. If your employer no longer exists or is unable to complete the form, there are alternate ways to document your coverage, but you should contact Social Security directly to work through that.

How This Applies in Utah

What This Means For You

For you, this means if you are still working at 65 and plan to delay Medicare Part B, keep records of your employer coverage so the enrollment process goes smoothly when you are ready to sign up.

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.