Medigap vs. Medicare Advantage for $3M+

If you have $3 million, which Medicare path should you take? Not the cheaper one. The one that buys you unrestricted access to care and protects that access before a diagnosis can take it off the table.

This is the fork every retiree hits at 65. Original Medicare plus a Medigap supplement, or Medicare Advantage. For most of the country the decision turns on cost. For an affluent household, cost is the wrong axis, and choosing on premium alone is how people quietly trade away the thing money was supposed to buy them.

The two roads

Original Medicare (Parts A and B) covers hospital and outpatient care but leaves you exposed to deductibles, coinsurance, and a catastrophic ceiling that doesn’t exist. A Medigap policy fills those holes. You pay a monthly premium, and in return your costs become predictable and you can see any provider in the country who takes Medicare. You add a standalone Part D plan for drugs.

Medicare Advantage replaces all of that with one private plan. Lower premium, often with dental and vision folded in, but you’re inside a network with referrals and prior authorizations. I break down its internals in the Medicare Advantage deep dive.

The honest summary: Advantage usually costs less per month and constrains your care. Medigap usually costs more per month and removes the constraints. Everything else is detail.

Why money flips the math

Here’s the second-order point most comparisons miss. The case for Advantage is that it saves money. But if you’ve got $3 million-plus, a few hundred dollars a month in premium is rounding error against your portfolio. You’re optimizing a variable that barely moves your life.

What you actually want at this level is access. The unrestricted ability to fly to the best specialist for a rare cancer, to skip the prior-authorization fight when weeks matter, to keep your doctors when you move between homes in two states. That’s what Medigap buys, and it’s exactly what Advantage’s low premium asks you to give up.

So the wealth that makes premium savings irrelevant is the same wealth that makes access priceless. For most $3M-plus households, that points to Original Medicare plus a strong Medigap plan. The Medigap flavors, mainly Plan G versus Plan N, get compared in Plan G vs. Plan N.

The lock-in nobody factors in

The decision feels reversible. It mostly isn’t, and that’s the part I lean on hardest with clients.

When you first enroll in Part B, you get a one-time Medigap open enrollment window where insurers must sell you any policy at the standard price, no health questions asked. Outside that window, in most states, Medigap is medically underwritten. Insurers can charge you more or turn you down based on your health.

That changes everything about the choice. Pick Advantage at 65 to save money, develop a serious condition at 74, and try to switch to Medigap, and you may find it priced out of reach or simply unavailable. The cheaper road can quietly become a one-way road. Choosing Medigap at 65 locks in your guaranteed right while you’re healthy enough to qualify. For a household that can easily afford the premium, paying up front to keep the door open is the obvious trade. It’s the Medicare surprise that costs the most.

When Advantage still makes sense at this level

I won’t pretend it’s never right. Advantage can fit even an affluent retiree who genuinely prefers a managed, all-in-one plan, whose top doctors are in-network, who doesn’t travel for care, and who values the out-of-pocket cap and bundled extras. Some people want the simplicity and don’t want to think about it again. That’s a legitimate preference, not a mistake.

What I push back on is choosing Advantage to save money you don’t need to save, while handing back access you can’t easily get back. That’s optimizing the small number and ignoring the large one.

How I’d frame the decision

A few questions that cut through it:

• Do you want to see any specialist in the country without a referral? If yes, Medigap.
• Will you live in or travel between multiple states? Networks make Advantage painful across state lines. Medigap travels.
• Is keeping the guaranteed right to Medigap worth a higher premium now? For $3M-plus, almost always yes.
• Would you rather pay more for predictability, or less for managed care? That single preference decides it.

For most households with real money, the answer is Original Medicare plus Medigap, chosen at 65 while your health still lets you. You’re not buying the cheaper plan. You’re buying access and locking it in, which is the one thing your money is supposed to be able to do.