Medigap Plan F Closed to Newly Eligible Buyers in 2020. The Millions Still Holding It Can’t Simply Switch Out

Anyone still holding Medigap Plan F has watched the renewal notices climb. Whether they’re climbing faster than a neighbor’s Plan G depends on the carrier, the state, the policy form and the rating method, and there’s no national rule that says they must. But the pool behind those notices is changing in a way that creates real upward pressure, and it’s worth understanding before the next renewal lands.

What MACRA Actually Did

The Medicare Access and CHIP Reauthorization Act of 2015 (MACRA) closed Plans C and F to anyone newly eligible for Medicare on or after January 1, 2020. People who were already eligible before that date kept their plans, and some of them can still buy Plan F today. That distinction gets flattened constantly, including by people selling Medigap.

Plan F is not nationally closed. The NAIC has been explicit that MACRA did not legally close existing Plan F blocks. What changed is that the pipeline of new entrants narrowed sharply, to a group that shrinks a little more every year as the pre-2020-eligible population ages. Individual carriers can and do close particular policy forms or rating blocks, and if yours has, that’s a company decision rather than a federal one. It’s worth asking which situation you’re actually in.

Why a Shrinking Pool Creates Pressure

Insurance pools stay affordable when younger, healthier enrollees keep arriving to dilute the claims of older, less healthy members. Plan F’s inflow has narrowed to a closing group, so the average member is getting older without much offsetting it. That can produce adverse selection. Claims per member may rise faster than in a plan still taking all comers. Carriers file for larger increases. The healthiest holders shop elsewhere, and the ones who can pass underwriting leave, which concentrates risk further among those who stay.

None of that is guaranteed in any particular market or filing. But it’s the direction the structure pushes, and it’s why Plan F’s first-dollar coverage cuts both ways: paying the Part B deductible that Plan G leaves to the enrollee is exactly what attracts heavy users of care, which is the same feature that concentrates claims inside the pool. NAIC-derived data put Plan F enrollment around 4.5 million in 2024, down from roughly 4.9 million in 2023, accounting for about one-third of the Medigap market. Still millions of people, but fewer than the year before.

The Door Out Is Narrower Than It Looks

The obvious move is Plan G, which covers what Plan F does except the $283 annual Part B deductible for 2026; it also still takes new entrants. Here’s what most holders discover only when they try. Outside the original six-month Medigap open enrollment window, insurers in most states can medically underwrite a Plan G application and decline it or price it higher. Some states offer broader guaranteed-issue rights, including New York, Connecticut, Massachusetts and Maine, though the scope and conditions differ meaningfully by state.  

The federal default is harsher: a 78-year-old with a diabetes diagnosis and a stent may not be able to move at all. The people with the most reason to leave are the ones a receiving insurer is most likely to refuse.

Run the Numbers Before Your Next Renewal

Medigap has no annual federal enrollment season, so the time that matters is whenever your rate notice arrives.

Compare total annual cost, not premium alone. On Plan G you pay the $283 Part B deductible yourself, then nothing further for covered Part B services. On Plan F that deductible is covered. Spread across a year, that deductible works out to about $23.58 a month. If Plan F costs you more than that above a Plan G quote, Plan G is generally the cheaper of the two on those items alone. The standard Part B premium is $202.90 in 2026, up from $185.00 in 2025, and that’s a fixed claim on any Social Security raise before Medigap enters the picture. We mapped the rest of the surcharges and coverage gaps in a free guide to Medicare’s hidden bills.

Three Things Worth Doing Now

Underwriting gets harder with each birthday, not easier, which makes this one of the rare Medicare decisions where acting early is worth more than deciding well:

• Ask your carrier for a written three-year rate history on your policy form, then get a current Plan G quote for your age and ZIP. Hold the difference against the $23.58 line.
• Learn what your state actually allows. The protections vary in scope and conditions, so call your state insurance department rather than relying on a comparison site’s summary.
• Price high-deductible Plan G as an alternative, not an escape hatch. The premium runs lower and annual exposure is capped at a fixed deductible, but it’s still a Medigap policy. Outside a protected window it requires underwriting too, and it can decline the same applicant standard Plan G would.

The cohort is likely to keep aging and the filings are likely to keep coming, though neither is certain in any given year. What is reasonably certain is that the longer you wait, the harder the underwriting question is to answer.

Contact [email protected] for any questions or corrections.