Updated August 7, 2026. Quick answer: the Annual Notice of Change is the letter your Medicare Advantage or Part D plan sends each autumn to tell you what it is changing for January 1. 🔴 It arrives before the Annual Election Period on purpose — the regulation requires at least 15 days of lead time — and that gap is the entire point of the letter. It is the plan telling you what it will look like next year while you can still leave.
The timing rule, and why it exists
For changes taking effect on January 1, the regulation requires the plan to:
notify all enrollees at least 15 days before the beginning of the Annual Coordinated Election Period
For changes that take effect at any other time, the plan must give notice at least 30 days before the intended effective date.
Read the date on the envelope as a countdown, not a formality. The lead time exists so the letter lands while you can still act on it.
What to actually compare
The ANOC is written as a this-year-versus-next-year document, and the differences are the only part worth your time: the premium, the deductible, the copays for the services you actually used this year, the out-of-pocket maximum, and — for drug coverage — whether your specific medications moved tier or left the formulary.
⚠️ A tier change is a price change even when the premium did not move. A plan can hold its headline premium flat and still cost you considerably more next year through the formulary.
Network is the other silent one: “the MA organization must provide enrollees notice of a termination of a contracted provider”. A plan whose numbers are unchanged can still have lost your doctor.
What it is not
It is not a bill, and it is not a renewal you must sign. Doing nothing usually means staying in the plan as changed — which is exactly why the letter matters. The default is acceptance.
Sources
Notice requirements quoted from 42 CFR § 422.111 (disclosure requirements, changes in rules and provider-network notice), via eCFR, retrieved 7 August 2026. Figures change every plan year and are plan-specific — this page deliberately prints no premium, deductible or out-of-pocket number, because the only ones that matter are the ones in your own letter.
Related: the Medicare notices index.