Medicare Participation for 2027 Closes December 31. Doing Nothing Is Also a Decision.

Once a year, Medicare asks every physician, practitioner and supplier the same question: will you participate next year? In its November 12, 2026 MLN Connects newsletter, the Centers for Medicare & Medicaid Services (CMS) set the date for calendar year 2027. The decision is due by December 31, 2026, whatever your status is today.

CMS also says that a practice happy with its current status does not need to do anything. That is why most practices never look at the question. The status chosen years ago, sometimes by a previous owner or manager, simply rolls into another year.

What the two statuses mean on a claim

A participating practice accepts assignment on every Medicare-covered claim. In CMS's words: "By accepting assignment, you agree to accept Medicare-allowed amounts as payment in full." In return, Medicare pays the full Physician Fee Schedule allowed amount, pays the practice directly, and forwards claim information to the patient's Medigap insurer.

A non-participating practice is still enrolled in Medicare and still bills Medicare. Three things are different:

• Medicare's allowed amount is 5 percent lower than the participating amount.
• The practice can accept assignment claim by claim. When it does not, it can charge the patient more than the allowed amount, up to the limiting charge. Under 42 CFR 414.48, that limit is 115 percent of the fee schedule amount for non-participating suppliers.
• CMS says non-participating suppliers have limited appeal rights.

The arithmetic behind the 5 percent

Take a service with a participating allowed amount of $100. This is an example, not a fee schedule figure.

For a non-participating practice, the allowed amount is $95. If the practice accepts assignment on that claim, $95 is the total it can collect from Medicare and the patient together. If it does not accept assignment, the most it can charge is 115 percent of $95, which is $109.25.

So non-participation only pays more when the practice bills unassigned claims and collects the difference from patients. Medicare tells patients that with a non-participating provider, "You might have to pay the full amount at the time of service." That moves collection work to your front desk. A non-participating practice that accepts assignment on most claims is simply working for 95 percent.

Who must act, and how

The CMS participation page lists three cases that need action. The window runs from mid-November through December 31, and a change takes effect on January 1.

• Not participating now, and want to participate in 2027: complete the Medicare Participating Physician or Supplier Agreement (Form CMS-460) and mail a copy to your Medicare enrollment contractor.
• Participating now, and want to stop: write to each Medicare Administrative Contractor (MAC) that receives your Part B claims. CMS says the notice "must be postmarked before December 31 of the previous effective year."
• Newly enrolling: submit the CMS-460 with the enrollment application.

Five checks before December 31

This is general information, not legal or financial advice. A practice can start with these steps:

• Confirm your current status with your MAC for every billing entity and tax ID. Do not rely on memory. Groups that merged or bought another practice can hold different statuses.
• If you are non-participating, pull 12 months of Medicare claims and count how many were assigned. If most were, ask what the 5 percent is buying.
• For unassigned claims, compare what you billed patients above the allowed amount with what you actually collected, and add the staff time spent collecting it.
• Check your fee schedule against the limiting charge for your most common codes. A charge above the limit on an unassigned claim is a compliance problem, not a pricing choice.
• If you decide to change, send the form or the letter with tracking, keep a dated copy, and do it before the holiday week.

Make it a decision, not a default

CMS had not posted its 2027 letter to providers when this article was written. Its participation page said to check back soon, so look there for the letter and any contractor instructions before you mail anything.

Neither status is right for every practice. What matters is that someone looks at the numbers and chooses. The choice costs an hour in November and it holds for all of 2027. If you want a second set of eyes on what Medicare is paying against what it allows, a revenue review can look at one payer and one quarter.