CMS L564 Form Federal Retiree: How to Prove Employer Coverage for Medicare Part B

Why CMS-L564 Matters for Federal Retirees

When federal employees delay Part B while covered through active employment, they need to prove that job-based coverage when they enroll after age 65. If they retire, the Part B Special Enrollment Period generally lasts 8 months after employment or job-based coverage ends. Without proof, Medicare charges the late enrollment penalty: 10% of the standard Part B premium for each full 12-month period you could have been enrolled but weren't.

For a federal retiree who delayed Part B by five years, that penalty would add about $101/month to the standard $202.90 premium — permanently. CMS-L564 (Request for Employment Information) is the form that prevents this.

What CMS-L564 Proves

The form documents group health plan coverage based on current employment. For a federal retiree, FEHB coverage obtained through active employment can support the SEP, but retiree FEHB by itself is not current-employment coverage. CMS-L564 documents the employment-based coverage; CMS-40B is the Part B application.

CMS-L564 is paired with CMS-40B (Application for Enrollment in Medicare Part B). You file both together when requesting a Special Enrollment Period (SEP) to enroll in Part B outside the standard General Enrollment Period.

Who Needs to File CMS-L564

Federal employees who delayed Part B while actively employed. If you skipped Part B at 65 because you were covered by FEHB through active federal employment and you retire within the last 8 months, CMS-L564 can document that coverage for the SEP. Submit it with CMS-40B.

Former federal employees with job-based coverage gaps. If you separated from federal service, lost job-based coverage, and are enrolling in Part B more than 8 months after coverage ended, L564 alone won't help — the SEP is only available within 8 months of losing employer coverage. After that window, you'd generally use the General Enrollment Period and may face a late penalty for the uncovered period.

PSHB postal retirees typically don't need L564. Since PSHB requires Medicare Part B enrollment to maintain coverage, most postal retirees enroll during their Initial Enrollment Period and never need a SEP. If a recently retired postal employee is using an employment-based SEP, follow OPM and SSA instructions for documenting the coverage.

How to Get CMS-L564 Completed

The form has two sections:

Section A: Completed by You

Your name, Medicare number (or Social Security number), date of birth, and the dates you're requesting coverage documentation for. List the group health plan coverage period you want documented, matching Section B.

Section B: Completed by Your Employer or Plan Administrator

This is where federal retirees face a procedural question: who fills out Section B?

If you're currently employed or recently separated: Ask your employing office or agency HR to complete Section B documenting coverage through current employment.

If you're already an OPM annuitant: Use OPM's Retirement Services support process to request a completed CMS-L564. OPM verifies eligibility and returns the form by email or mail.

The required information in Section B is straightforward: the name of the group health plan, the dates of coverage, and whether the coverage was based on current employment. Retiree FEHB coverage alone does not turn that answer into current-employment coverage.

Filing CMS-L564 and CMS-40B Together

Once Section B is completed, submit both CMS-L564 and CMS-40B to your local Social Security office. You can:

1. Apply online at ssa.gov/benefits/medicare/ and submit CMS-40B with the completed L564
2. Fax both forms to your local SSA office
3. Mail both forms to your local SSA office

SSA determines the processing time and Part B effective date under the SEP rules. State the requested Part B start month in the remarks section of CMS-40B and follow SSA's instructions.

The 8-Month SEP Window

The Special Enrollment Period for Part B generally lasts 8 months from the date active employment or job-based coverage ends. For federal retirees, retiree FEHB coverage does not keep this employment-based SEP open indefinitely.

This is the key point for FEHB retirees: if you retire within the applicable 8-month SEP window, use CMS-L564 and CMS-40B to document the active-employment coverage; do not assume retiree FEHB alone creates an SEP.

If you cancel FEHB, that does not create a new employment-based SEP. Ask SSA about your enrollment options before canceling coverage.

Avoiding Common Delays

• Get L564 completed before you need it. If you're considering Part B enrollment in the next 6 months, start with your former employing office or OPM's support process, not your FEHB carrier.
• Keep copies of your FEHB enrollment records. Annual Open Season confirmations, plan brochures with your enrollment code, and SF 2809 copies all support your coverage claim if L564 processing hits a snag.
• Don't confuse CMS-L564 with CMS-40B. L564 proves coverage; 40B is the actual enrollment application. You need both.

The Federal Retirement Countdown Checklist integrates Medicare enrollment decisions into the 12-month pre-retirement timeline, including when to request L564 and how to coordinate the Part B enrollment date with your FEHB plan's Medicare coordination benefits.