Not all insurance companies offer Part D, but most major ones do
Medicare Part D (prescription drug coverage) is optional for insurance companies to offer. The federal government does not require every insurer to participate. However, most large national insurers and many regional plans do offer Part D coverage because the market demand is strong — people on Medicare need prescription drug coverage, and insurers want that business.
The companies that do participate in Part D must follow federal rules about what drugs they cover, how much they charge, and how they handle appeals. But the decision to participate at all is up to each company. This means your options depend partly on which insurers operate in your state and which ones have chosen to enter the Part D market.
If you are looking for Part D coverage, you will find plans from insurers like UnitedHealthcare, Humana, CVS Health, Aetna, and Cigna in most states. Smaller regional insurers may also offer Part D plans. The number and type of plans available to you depends on where you live.
Key Takeaways
- Insurance companies choose whether to offer Part D plans — the federal government does not mandate participation.
- Most major national insurers offer Part D coverage, but availability varies by state and region.
- Every Part D plan that does exist must follow the same federal rules about coverage, cost-sharing, and appeals, even though different companies run them.
- If you cannot find Part D coverage from a private insurer in your area, you can enroll in a standalone Part D plan through Original Medicare.
- You can change Part D plans every year during the annual enrollment period, even if your current insurer continues to offer coverage.
How Part D plans are structured and who runs them
Part D is administered through private insurance companies under contract with Medicare. The federal government sets the rules, but the insurers handle enrollment, claims, customer service, and formulary decisions (the list of drugs they cover). This is different from Original Medicare Parts A and B, which the government runs directly.
Because Part D is a private market, insurers can decide which states to operate in, which drugs to cover, and how much to charge. They can also decide to stop offering Part D in a particular state or to exit the program entirely. When an insurer stops offering Part D in your area, Medicare notifies affected members and gives them time to switch to another plan.
You have two ways to get Part D coverage: through a Medicare Advantage plan (Part C) that includes drug coverage, or through a standalone Part D plan paired with Original Medicare. Both types are run by private insurers, but the insurers offering each type may be different.
What happens if no Part D plans are available in your area
This is rare, but it can happen. If you live in a county where no insurer offers Part D coverage, Medicare has a fallback program called the Part D Retiree Drug Subsidy Program for certain groups, though this mainly applies to retirees with employer coverage. For most people in this situation, Medicare will allow you to enroll in a Part D plan from a neighboring county or state if one is available.
If you truly cannot find any Part D coverage and you do not have other drug coverage, you should contact Medicare directly at 1-800-MEDICARE to discuss your options. They can tell you whether you may have access to for any special enrollment periods or alternative programs.
Going without Part D coverage when you are may be able to access can result in a late enrollment penalty if you join later. The penalty is added to your Part D premium for as long as you have coverage, so it is worth exploring all options before going uninsured.
How to find which insurers offer Part D in your state
The easiest way to see which companies offer Part D plans where you live is to use Medicare's Plan Finder tool at Medicare.gov. You enter your zip code, and the tool shows you every Part D plan available in your area, along with the insurer name, monthly premium, and which drugs are covered.
You can also call 1-800-MEDICARE and ask a representative which insurers offer Part D in your county. They can give you the names and phone numbers of the companies and help you understand the differences between plans.
State Health Insurance information Programs (SHIPs) also offer free counseling to help you compare Part D plans. A SHIP counselor can walk you through the options and answer questions about coverage, costs, and how to switch plans.
Rules that explore to every Part D plan, regardless of the insurer
Even though different companies run Part D plans, they all must follow the same federal standards. Every plan must cover at least two drugs in each major drug category, and they must cover all drugs used to treat certain conditions like cancer, HIV, and mental illness. This is called the "protected classes" rule.
Every Part D plan also has the same cost structure: a deductible (which can be up to $545 in 2024, though this amount changes yearly), a copay or coinsurance amount you pay for each prescription, and a coverage gap (sometimes called the "donut hole") where you pay more out of pocket. Once you spend enough on drugs, catastrophic coverage kicks in and your costs drop again.
All Part D plans must allow you to appeal if they deny coverage for a drug you need, and they must have a process for you to request an exception if a drug is not on their formulary. These appeal rights are the same across all insurers.
When you can switch Part D plans or insurers
You can change Part D plans once a year during the Annual Enrollment Period, which runs from October 15 to December 7. This applies whether you are switching to a different plan from the same insurer or moving to a plan from a different company entirely. Your new coverage starts January 1.
You can also switch outside the enrollment period if you experience a may have access to life event, such as moving to a new state, losing other drug coverage, or becoming may be able to access for Extra Help (a federal program that helps pay Part D costs). You have 60 days from the event to make the change.
If your current insurer stops offering Part D in your area, Medicare will send you a notice and give you a special enrollment period to switch to another plan without waiting for the annual period.
What to do if an insurer stops offering Part D coverage
When an insurer exits the Part D market in your state or county, Medicare notifies you by mail at least 30 days before coverage ends. The notice tells you which other plans are available and how to enroll in a new one. You do not have to wait for the Annual Enrollment Period — you can switch when ready.
If you do not choose a new plan by the important date, Medicare may automatically enroll you in another Part D plan to avoid a gap in coverage. However, it is better to choose your own plan so you get one that matches your prescriptions and preferred pharmacy.
During this transition, you should review your current medications and check which drugs are covered under the new plans available to you. Some plans may cover your drugs differently or require prior authorization, so it is worth comparing before the switch takes effect.
Frequently Asked Questions
Can Medicare force an insurance company to offer Part D?
No. Part D is a voluntary program for insurers. Medicare sets the rules that participating companies must follow, but it cannot force a company to participate. Insurers decide based on business considerations like whether they think they can operate profitably in a particular market.
If I have coverage through my employer, do I need Part D from an insurance company?
Not necessarily. If your employer or former employer offers retiree drug coverage that is at least as good as Part D (called "creditable coverage"), you do not have to enroll in Part D. However, if you lose that coverage, you can enroll in Part D without a penalty as long as you do so within 63 days of losing the employer coverage.
What if my Part D insurer raises prices or changes my drug coverage mid-year?
Part D plans can change their formularies (the drugs they cover) during the year under certain circumstances, though major changes are rare. If your insurer makes a change that affects your medications, you may may have access to for a special enrollment period to switch to a different plan outside the annual enrollment window.
Are all Part D plans from the same insurer identical?
No. Most large insurers offer multiple Part D plans with different premiums, deductibles, and drug coverage. You need to compare the specific plans available in your area, not just the company name. Use Medicare's Plan Finder to see all the options from each insurer.
What happens if I do not enroll in Part D when I first become may be able to access?
If you go without Part D coverage and do not have other creditable drug coverage, you will owe a late enrollment penalty when you eventually join. The penalty is 1% of the national average Part D premium for each month you were not covered, and it stays on your premium permanently.