Medicare Open Enrollment 2026: A Planning Guide for Advisors

Medicare's annual open enrollment period (OEP) runs from October 15 through December 7, 2026. Any changes made during this window take effect January 1, 2027. For clients already enrolled in Medicare — or approaching 65 — this is the most consequential coverage decision they make each year.

Here is what advisors need to know to help clients review their options and act before the deadline.

What clients can change during open enrollment

OEP is the one window when nearly every Medicare coverage decision is on the table:

One important caveat: switching back to Original Medicare from a Medicare Advantage plan does not automatically guarantee Medigap (Medicare Supplement Insurance) access. Outside of guaranteed issue situations, most states allow insurers to use medical underwriting — clients with pre-existing conditions may be declined or charged higher premiums. Proactively planning for Medigap before clients enter Medicare is far easier than navigating it after the fact.

Start with the ANOC

Every Medicare plan is required to send an Annual Notice of Change (ANOC) letter in September. The ANOC details what is changing for 2027: premiums, deductibles, cost-sharing, network changes, and drug tier adjustments.

If a client's plan hasn't changed materially and their health needs and prescriptions are stable, staying put may be the right call. If the ANOC shows a drug moved to a higher tier, a key specialist left the network, or premiums jumped significantly — it is worth shopping.

2026 open enrollment by the numbers

These are national averages. Actual plan availability and costs depend on the client's zip code, and the optimal plan depends on their specific prescriptions, preferred providers, and utilization patterns.

Planning considerations for advisors

The lowest-premium plan is rarely the best plan

Medicare Advantage plans with $0 premiums often offset that with higher cost-sharing at the point of care. Clients with chronic conditions or frequent specialist visits can pay significantly more out-of-pocket on a $0-premium plan than on one with a modest monthly cost. Help clients model expected utilization — not just compare premium lines.

Drug formularies change every year

A drug that was Tier 2 in 2026 may be Tier 4 in 2027. Clients on maintenance medications should enter their current prescriptions into the Medicare Plan Finder to compare total drug costs — not just premiums — across available plans. This matters most for clients on specialty biologics or newer branded medications.

Medigap timing is not forgiving

Clients considering a switch from Medicare Advantage back to Original Medicare need to understand their Medigap options before they make the switch. Guaranteed issue rights apply in limited situations: losing employer coverage, moving out of a plan's service area, or a plan being discontinued. Outside of those, health underwriting applies in most states. This is a planning conversation to have well before open enrollment, not during it.

IRMAA adds a surcharge on top of Part D premiums

Higher-income clients pay an income-related monthly adjustment amount (IRMAA) surcharge on top of whatever their Part D plan charges. For 2027, IRMAA determinations are based on 2025 MAGI. This surcharge is separate from the plan's stated premium and frequently surprises clients who see only the plan premium advertised.

December 7 is a hard deadline

Changes not submitted by December 7 will not take effect January 1. Clients who miss the window must generally wait until next year's OEP unless they qualify for a Special Enrollment Period (such as moving, losing other coverage, or qualifying for low-income programs).

Resources for client conversations

• Medicare Plan Finder — compare plans side by side, including estimated drug costs
• Medicare Rights Center — independent, consumer-focused guidance on Medicare rights
• SHIP (State Health Insurance Assistance Programs) — free, unbiased local counseling in every state

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Sources: Medicare.gov Open Enrollment; Medicare Rights Center. Plan averages reflect CMS 2027 preliminary data; verify current figures at medicare.gov.