How do I enroll in Part B after leaving employer coverage?

Quick Answer

When you leave employer coverage, you have an 8-month Special Enrollment Period to sign up for Medicare Part B without a late penalty. You'll need to file Form CMS-40B and, in most cases, Form CMS-L564 to prove you had employer coverage.

Detailed Explanation

Losing employer coverage triggers a Special Enrollment Period, which gives you 8 months to sign up for Part B without facing a late enrollment penalty. That 8-month window starts the month after your employer coverage ends, or the month after your employment ends, whichever comes first. Don't wait for COBRA to run out. COBRA is continuation coverage, not employer-sponsored coverage in Medicare's eyes, and relying on it to delay Part B can lead to a penalty.To enroll, you'll complete two forms. Form CMS-40B is the actual Part B application. Form CMS-L564 is a request for employment information that your former employer fills out to confirm you had group health coverage. Once you have both completed, you can submit them to your local Social Security office, mail them, or in some cases handle it online through SSA.gov.If you're already receiving Social Security benefits, the process is slightly different and Social Security may reach out to you automatically. Either way, don't assume it happens on its own. It's worth calling Social Security directly or working with a licensed Medicare agent to make sure nothing falls through the cracks. Timing matters here, and a missed deadline can mean paying higher premiums for years.

How This Applies in Utah

What This Means For You

For you, this means acting quickly after leaving employer coverage is important, because the 8-month window moves fast and missing it leads to permanent premium penalties.

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.