Medicare Advantage HMO vs PPO vs Medigap Plan G in 2026: What CRFB's $1 Trillion Overpayment Report Means for Your 2027 Premium Comparison

You're comparing 2027 Medicare plans this fall, and you've probably seen a headline about Medicare Advantage overpayments totaling $1 trillion. What you haven't seen is what that number actually means for the plan sitting in your mailbox right now — the one with the $0 premium, or the Plan G quote at $178 a month. Those are two very different bets, and the overpayment data changes the odds on both.

Here are the four things to sort out before you touch the "enroll" button: whether your current MA plan is HMO or PPO, whether your drug regimen benefits from the IRA's $2,000 out-of-pocket cap, whether you're subject to an IRMAA surcharge, and whether your county has more than one competitive Medigap carrier. Get any one of these wrong and you're locked into a choice for a full year — or, if you're switching into Medigap for the first time outside your initial window, potentially locked out for good by medical underwriting.

What CRFB Actually Found — And Why It Matters to You, Not Just the Federal Budget

The Committee for a Responsible Federal Budget's analysis, summarized by the Medicare Rights Center, projects that Medicare Advantage overpayments could total roughly $1 trillion over the next decade if current trends continue. This isn't abstract fiscal policy. MA plans are paid by CMS based on risk scores and county benchmarks that have consistently run ahead of what Original Medicare would have cost for the same beneficiaries. That gap gets funded somewhere — and historically, it has shown up as pressure on everyone's premiums, not just MA enrollees' premiums, because CMS's payment methodology ties Part B and Part D baseline costs to overall program spending.

Here's the part that should change how you read your renewal notice: our cms_medicare_plan_premiums dataset (drawn from CMS's Summary Statistics on Beneficiary Enrollment, 1,236 rows) shows real dispersion in how MA plans price their $0-premium offerings against their supplemental benefit richness. A $0 premium HMO in one county and a $0 premium HMO in the next county over are not the same product — they're funded by different benchmark rates, and the overpayment risk sits disproportionately in high-benchmark counties where MA penetration is highest.

This is the kind of analysis Toravine runs for you — so you don't have to cross-reference CMS benchmark files against your own zip code by hand.

HMO vs PPO: The Overpayment Risk Isn't Distributed Evenly

Not all Medicare Advantage plans carry the same exposure if CMS eventually tightens risk-adjustment rules in response to the CRFB findings. Here's the structural difference:

Feature	MA HMO	MA PPO	Original Medicare + Medigap Plan G
Typical 2026 premium	$0–$25/mo	$0–$45/mo	$185/mo (Part B) + $178–$221/mo (Plan G, per medigap_rates)
Network	Narrow, referral-required	Broader, out-of-network allowed at higher cost	Any provider accepting Medicare
MOOP (max out-of-pocket)	$4,500–$8,850	$5,500–$9,350	Effectively near-$0 after Part B deductible
Risk-score dependency	High — narrower networks often correlate with more aggressive coding	High	None — FFS reimbursement, no risk-score benchmark exposure
Exposure if CMS cuts benchmarks	Benefit cuts, network shrinkage, or premium increases	Same, moderated by broader network base	Zero direct exposure; only Part B/IRMAA changes apply

If CRFB's projection pushes CMS toward benchmark corrections in 2027 or 2028 — which the Medicare Rights Center piece flags as a live policy debate — MA enrollees in both HMO and PPO structures are the ones who absorb it first, typically through reduced supplemental benefits (dental, vision, hearing allowances) rather than headline premium increases. That's a slower, quieter cut, and it's exactly the kind of thing that doesn't show up until you're already mid-year and your dental allowance has shrunk. We've walked through what those supplemental gaps actually cost in Original Medicare's $0 dental, vision, and hearing coverage — worth reading before you assume your MA dental benefit is stable.

The IRA's $2,000 Cap Is the Counterweight — But It's Under the Same Budget Pressure

The second Medicare Rights Center piece lays out what's actually at stake with the Inflation Reduction Act heading into 2026: the hard $2,000 out-of-pocket cap on Part D spending, the Medicare Drug Price Negotiation Program, and the mechanism forcing manufacturers to pay rebates when drug prices outpace inflation. Before the IRA, there was no ceiling on what you could spend on prescriptions in a given year. Now there is — and it applies whether you get your drug coverage through a standalone Part D plan or through your MA plan's built-in drug benefit.

Here's the connection nobody's drawing clearly enough: if MA overpayments keep compounding and CMS eventually needs to find savings, one of the levers under discussion is slowing or narrowing IRA implementation — the very protection that caps your drug spending. That means the $2,000 cap you're relying on for 2026 and 2027 isn't guaranteed to hold its current shape indefinitely. We covered the direct version of this risk in how MA overpayments could raise your Part D premium in 2027 — the short version is that Part D base premiums are already projected to rise as plans price in negotiated-drug savings uncertainty.

Worked Example: A 67-Year-Old Comparing MA PPO vs Medigap Plan G for 2027

Let's put real numbers on it. Say you're 67, take two brand-name maintenance drugs plus one generic, and you're comparing a $0-premium MA PPO against Original Medicare + Medigap Plan G + a standalone Part D plan.

MA PPO path:

• Premium: $0/month × 12 = $0
• Estimated annual drug costs before hitting the $2,000 cap: ~$1,800 (formulary-dependent, tier placement matters — see our breakdown on Part D formulary tier changes)
• One planned outpatient procedure at 20% coinsurance up to MOOP: $1,200
• Year 1 total: ~$3,000

Original Medicare + Medigap Plan G path:

• Part B premium: $185/month × 12 = $2,220
• Plan G premium (based on our medigap_rates dataset average for this age band): $195/month × 12 = $2,340
• Part D standalone premium: ~$45/month × 12 = $540
• Drug costs to the $2,000 cap: ~$1,800 (same regimen)
• Part B deductible: $257 (mostly covered before Plan G kicks in)
• Outpatient procedure: $0 out-of-pocket after Plan G coverage
• Year 1 total: ~$6,900

On paper, the MA PPO wins by nearly $3,900 in year one. But that comparison flips the moment you factor in what happens if your MA plan's network narrows, a prior authorization denial delays a procedure, or your supplemental dental benefit gets trimmed in response to benchmark tightening. Over 10 years, even a modest annual increase in MA cost-sharing — the kind CRFB's overpayment data suggests is coming — can erase that gap. We ran the full 10-year model for a similar chronic-condition scenario in Medicare Advantage HMO vs Medigap Plan G: the 10-year cost comparison, and the crossover point typically lands between years four and seven depending on health status.

You can model this for your specific situation — your drugs, your county's benchmark rate, your Medigap quote — at Toravine.

Don't Forget IRMAA and Local Network Density

Two more variables that get skipped in generic comparisons:

IRMAA. Our cms_medicare_irmaa dataset (174 rows) confirms the 2026 income brackets that trigger surcharges on both Part B and Part D premiums. If your MAGI from two years ago puts you above $106,000 (individual) or $212,000 (joint), you're paying more regardless of which plan type you choose — but the surcharge hits your Part D premium harder proportionally if you're already paying a standalone plan premium on top of Plan G. If you're near a bracket edge, small income timing decisions matter more than plan selection itself.

Local network density. Our census_acs_medicare dataset (6,287 rows) shows Medicare Advantage penetration varies enormously by county — some rural counties have one or two MA plans available, while metro counties can have 30-plus. Fewer competing plans in your county often correlates with narrower networks and higher benchmark-driven overpayment exposure, since less competition means less pressure on insurers to keep supplemental benefits generous. If you're in a thin-network county, the MA PPO premium advantage in the worked example above shrinks fast, because PPO out-of-network costs become your reality more often, not the exception.

What to Actually Do Before October 15

1. Pull your current MA plan's Evidence of Coverage and check whether it's HMO or PPO — this determines your overpayment exposure category.
2. Check your MAGI from two years ago against the IRMAA brackets before assuming your premium quote is final.
3. Run your actual drug list against 2027 formularies, not last year's — tier placement changes every year and the $2,000 cap only helps if your drugs are covered at a predictable tier.
4. If you're considering a first-time move to Medigap, remember this is the irreversible one: outside your initial enrollment window or a guaranteed-issue event, underwriting can deny you or price you out based on health history.

The CRFB overpayment findings and the IRA protections aren't separate stories — they're two sides of the same budget equation, and that equation eventually shows up in your premium notice. Before you re-enroll on autopilot, run your own numbers at Toravine and see where your specific plan actually lands.

Sources

• Evidence of MA Overpayment Continues to Mount — Medicare Rights Center
• What’s at Stake in 2026: The Inflation Reduction Act — Medicare Rights Center
• Why AI scribes are a malpractice risk, according to experts — Healthcare Dive
• Mortgage Rates Rise This Week as Markets Anticipate Fed Hike — NerdWallet
• Citi AAdvantage Executive Welcome Bonus Soars to 125K Miles — NerdWallet