If you offer prescription drug coverage through your company health plan, you owe a specific one-page notice to your Medicare-eligible employees before October 15 — every single year. Miss it, and an employee who delays enrolling in Medicare Part D can end up paying a higher premium for the rest of their life, with your missing letter at the center of the story.
This is one of the most commonly overlooked employer compliance chores in benefits administration. It takes minutes, costs nothing, and yet surveys of benefits advisors consistently find small employers who have never heard of it. Here is what the rule requires, the second filing most businesses forget entirely, and a simple annual routine that keeps you covered.
Two Separate Obligations, Not One
The Medicare Modernization Act created two distinct disclosure duties for employers that sponsor group health plans with prescription drug coverage. Owners constantly confuse them — or learn about only one. You likely owe both:
- A notice to people: Tell your Medicare-eligible plan participants, in writing, whether your drug coverage is "creditable" or "non-creditable." Due every year before October 15.
- A disclosure to the government: Report that same creditable-coverage status electronically to the Centers for Medicare & Medicaid Services (CMS). Due within 60 days after the start of your plan year.
They serve different audiences, run on different deadlines, and use different forms. Do them as a pair and neither will ever surprise you.
The October 15 Notice to Medicare-Eligible Individuals
Why October 15?
Medicare's annual election period for Part D prescription drug coverage runs from October 15 through December 7. Before that window opens, every person deciding whether to enroll in (or stay out of) Part D needs to know whether their employer coverage counts as a valid substitute. Your notice gives them that answer.
Who must receive it?
Anyone enrolled in (or eligible for) your prescription drug plan who is also eligible for Medicare Part D. In practice that means:
- Active employees age 65 and older
- Medicare-eligible spouses and dependents on your plan
- Disabled participants entitled to Medicare, regardless of age
- COBRA participants and retirees with drug coverage, if you offer it
Because tracking exactly who is Medicare-eligible is an administrative headache — and getting it wrong means someone misses a notice — most advisors recommend the pragmatic approach: send the notice to every plan participant every year. A plan sponsor that distributes the annual notice to all participants satisfies the obligation without maintaining a Medicare-eligibility roster. Many employers simply stuff it into open-enrollment packets each fall.
When else must you send it?
The pre-October 15 mailing is the annual headline, but the rules also require a notice at several other trigger points:
- Before a Medicare-eligible person's initial enrollment period for Part D
- Before the effective date of coverage for any Medicare-eligible individual who joins your plan mid-year (for example, a new hire over 65)
- Whenever your drug coverage ends or its creditable status changes
- Any time a participant requests one
A new hire packet that includes the current notice, plus the annual fall mailing, covers nearly all of these triggers automatically.
Creditable vs. Non-Creditable: What It Actually Means
Coverage is "creditable" if its actuarial value is expected to equal or exceed the value of standard Medicare Part D coverage — in plain terms, if your plan's drug benefit is on average at least as generous as Medicare's. If it falls short, it is "non-creditable."
This is not a judgment call you make by eyeballing the formulary. There are two legitimate ways to determine your status:
- Ask your carrier or third-party administrator. Fully insured employers can usually get a written creditable-coverage determination letter from their insurer each year. Self-funded plans can ask their TPA or pharmacy benefit manager. Get this confirmation in writing and keep it with your benefits records.
- Use the simplified determination method or an actuarial analysis. CMS permits most plan designs to use a simplified checklist-style determination; plans with unusual designs (very high deductibles paired with limited drug coverage, for instance) may need an actuary's sign-off. Your benefits broker can tell you which path fits your plan.
Two practical notes. First, most mainstream employer PPO and HMO plans with standard drug formularies pass the test — but "most" is not a determination, so confirm it every plan year rather than assuming last year's answer still holds. Benefit designs change, and a change in deductible, out-of-pocket maximum, or formulary can flip your status. Second, if your coverage is non-creditable, you still send the notice — you just send the non-creditable version. Silence is not an option in either case.
What Goes in the Notice and How to Deliver It
CMS publishes model notices (in English and Spanish) for both creditable and non-creditable coverage, and using them verbatim is the safest course. The model language explains what creditable coverage means, what happens if the person delays Part D enrollment, and who to contact with questions. You are permitted to customize, but every required content element must survive the edit — so unless counsel reviews your draft, stick to the model form.
Delivery rules are flexible but have guardrails:
- First-class mail to the employee's home always works.
- Bundling with open-enrollment or annual materials is explicitly accepted and is how most employers comply.
- Electronic delivery is allowed only if it meets federal electronic-disclosure standards — generally, hand-delivery to someone with work-computer access as part of their job, or affirmative prior consent with hardware and software disclosures. Posting the notice on the intranet alone does not cut it.
One more recordkeeping point that matters more than it sounds: keep proof you sent it. Save a copy of the notice version you distributed, the distribution list or mailing vendor receipt, and the date. If an employee ever disputes receiving it — typically discovered years later, when a penalty appears on their Medicare premium bill — your proof of mailing is your defense. Benefits paperwork belongs in a permanent, organized file, not in someone's inbox.
Why This Letter Matters: The Lifetime Late-Enrollment Penalty
This is the part to take personally, because the consequence of a missing or wrong notice lands on a real person you employ.
Anyone who goes 63 or more continuous days without Part D or other creditable drug coverage after becoming eligible faces a late-enrollment penalty: 1% of the national base beneficiary premium for every full month without creditable coverage, added to their Part D premium for as long as they carry Part D — effectively for life. With the 2026 base premium at $38.99, a two-year gap works out to roughly 24% of $38.99, or about $9.40 extra every month, recalculated each year as the base premium changes. The amount grows with every uncovered month and never goes away.
An employee holding your creditable-coverage notice can prove they had qualifying coverage and avoid the penalty entirely. An employee who never got the notice may delay Part D enrollment believing the company plan suffices — only to learn at 67 or 68 that the plan was non-creditable and the penalty clock has been running. That is a painful conversation to have with a loyal employee, and it is entirely preventable with a one-page annual letter.
The CMS Filing Most Employers Forget
Separate from the notice to individuals, plan sponsors must disclose their creditable-coverage status directly to CMS through its online Disclosure to CMS Form. The deadlines:
- Within 60 days after the start of each plan year. For calendar-year plans, that lands on March 1 in most years (March 2 in some years). Mark it now.
- Within 30 days after your drug plan terminates.
- Within 30 days after any change in creditable status — for example, a mid-year plan redesign that flips you from creditable to non-creditable.
This filing applies whether your plan is fully insured or self-funded, and whether your drug coverage is primary or secondary to Medicare. The main exemption: if you offered no outpatient prescription drug benefits to any Part D-eligible person on the first day of the plan year, no disclosure is due for that year.
Note the calendar logic: the CMS disclosure (early in the plan year) and the participant notice (every fall) are six months apart, which is exactly why one gets done and the other gets forgotten. Put both on the same compliance calendar and treat them as one task with two due dates.
Your Annual Compliance Routine
Here is the whole program in five steps:
- At plan renewal: Confirm your creditable-coverage status in writing — carrier letter, TPA confirmation, or actuarial determination. File it where you keep plan documents.
- Within 60 days of the plan year start: Submit the electronic disclosure to CMS, and save the confirmation.
- Before October 15: Distribute the creditable (or non-creditable) notice to all plan participants, ideally inside open-enrollment materials. Save the version sent, the recipient list, and mailing receipts.
- Year-round: Include the current notice in new-hire packets for Medicare-eligible joiners, and re-send within 30 days of any termination or status change.
- Keep everything: Determination letters, CMS confirmations, notice copies, and distribution proof, retained with your other benefits records for at least as long as you keep plan documents.
Common mistakes to avoid
- Assuming last year's status carries over. Re-verify every plan year; formulary and deductible changes can flip the answer.
- Sending only to employees over 65. Medicare eligibility also reaches younger disabled participants and eligible dependents. Send to all participants and skip the roster problem.
- Posting to the intranet and calling it done. Electronic delivery has specific consent and access requirements — when in doubt, mail it.
- Doing the October notice but skipping the CMS filing. They are separate duties with separate deadlines; calendar both.
- Tossing the proof. The notice protects your employees; the proof of mailing protects you.
Keep Your Benefits Paperwork Organized From Day One
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