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Medicare Advantage HMO vs. PPO: why every Sioux Falls plan is a PPO in 2026

Nationally, most Medicare Advantage plans are HMOs. In Minnehaha County, every standard plan is a PPO — and that quietly changes what "network" means for you.

If you've heard that Medicare Advantage plans lock you into a small network and make you get a referral for everything, that's true for an HMO — but it isn't true for any of the 5 standard Medicare Advantage plans sold in Minnehaha County for 2026, because every one of them is built as a PPO. That's a real, sourced fact about this specific market, not a coincidence of how the plans happen to be named. It changes how you should think about comparing them.

Every figure below comes from the CMS PY2026 Medicare Advantage/Part D Landscape file, cross-checked against KFF's own analysis of that same CMS data and Medicare.gov's plan-type comparison. No invented numbers, no guessing at what a plan "probably" covers.

This matters for three different readers, and it means something slightly different to each one. If you're turning 65, every Medicare Advantage flyer that lands in your mailbox this year is describing a PPO, whether the letters "HMO" or "PPO" appear on the envelope or not — so the "will I need a referral" worry you may have heard about from friends in other states largely doesn't apply here. If you're already enrolled in one of the five standard plans, this is a chance to confirm you actually understood what you signed up for, and to know what would change if a carrier ever did file an HMO in a future year. And if you're an adult child helping a parent compare options from out of state, this is the one local fact that keeps the comparison honest — don't let a national explainer written for an HMO-majority market set your parent's expectations.

What HMO and PPO actually mean

Both letters describe the same thing: how a private Medicare Advantage plan controls your access to care. The two structures differ on exactly two questions that matter to your wallet and your calendar.

Source: Medicare.gov — Compare types of Medicare Advantage Plans; local plan counts from CMS Medicare Advantage / Part D Landscape (PY2026), PY2026.

An HMO — Health Maintenance Organization — generally requires you to stay inside the plan's network of doctors and hospitals, with coverage outside it limited to true emergencies or urgent care while you're traveling. Want to see a specialist? Most HMOs require your primary care doctor to send a referral first. A PPO — Preferred Provider Organization — drops the referral requirement and lets you see an out-of-network provider if you're willing to pay more for it. There's also HMO-POS, a hybrid that adds limited out-of-network coverage to an HMO base, and PFFS (Private Fee-for-Service), a third structure where you can visit any Medicare-approved provider who agrees to the plan's payment terms, no referral needed. Minnehaha County's 2026 roster doesn't include either of those hybrids among the standard plans — just PPO, plus two special-needs HMOs covered below.

Original Medicare sits outside this whole conversation. It has no network and no referral requirement of any kind — you can see any provider nationwide who accepts Medicare assignment. The HMO-versus-PPO question only exists once you step into Part C, Medicare Advantage, where a private carrier is managing your network on Medicare's behalf in exchange for taking on the financial risk.

The Sioux Falls reality: every standard plan is a PPO

Here's the full 2026 Minnehaha County roster of Medicare drug-carrying plans — all 15 of them — with the network type spelled out plainly, so you can see exactly what backs the claim above.

Source: CMS Medicare Advantage / Part D Landscape (PY2026), Minnehaha County, PY2026.

Look at the Network column and a pattern jumps out: 9 plans carry a PPO structure, and only 2 carry an HMO structure — and those 2 aren't even available to the general Medicare population. They're Institutional Special Needs Plans, built for people who already live in a nursing home. If you're comparing plans as a typical Medicare beneficiary in Sioux Falls, Brandon, Harrisburg, or Tea, you're choosing among PPOs, full stop. That also means the four Dual-Eligible Special Needs Plans, for people on both Medicare and Medicaid, are PPO-structured too — a detail that surprises people who assume "Special Needs Plan" automatically means a tighter HMO network.

Why South Dakota looks different from the national picture

The national default is an HMO. Locally, it's flipped. Here's the actual gap, side by side.

Source: KFF, Medicare Advantage 2026 Spotlight: A First Look at Plan Offerings (published December 9, 2025) for the national figures; CMS Medicare Advantage / Part D Landscape (PY2026) for Minnehaha County, PY2026.

Nationally, HMOs made up 57% of all 2026 Medicare Advantage plans and local PPOs made up 42% (regional PPOs took the remaining 1%), per KFF's own analysis of CMS's landscape file — though that HMO share has been shrinking for years, down from 71% back in 2017 as carriers filed more PPOs. On the enrollment side, KFF's most recent figures put 59% of Medicare Advantage enrollees in HMOs versus 40% in PPOs as of 2025. Whichever way you slice it, HMOs are still the more common structure across the country. Minnehaha County runs the other direction entirely for its standard plans, and that's worth knowing before you assume a Medicare Advantage plan here will behave like the one your sister has in Phoenix or your neighbor's daughter has in Chicago.

Why it happens: this is a carrier filing choice, not a rule

Nothing in federal law bars an HMO Medicare Advantage plan from Minnehaha County. Every year, each insurance carrier decides which plan types to file with CMS for each county, based on how confident it is that it can build an adequate network and price the product to compete. For 2026, the five carriers active in the county — Aetna/CVS, Sanford Health, UnitedHealthcare, Wellmark/BCBS, and Medica — all chose to file their standard products as PPOs (Medica's are technically Medicare Cost plans, a different animal covered below). That's a market decision, re-made every plan year. It's entirely possible a carrier files an HMO here for 2027 or 2028; the way to know is to check the current year's landscape file before you enroll, not to assume this year's pattern holds forever.

The national trend actually points the other way, which makes the local pattern more striking, not less. HMOs have gone from 71% of all Medicare Advantage plans in 2017 down to 57% in 2026, per KFF's own analysis of CMS's landscape data — carriers nationally have been filing more PPOs every year, not fewer. Minnehaha County simply got there first: every standard carrier here had already made the PPO choice well before the national market started catching up. Whether that's because rural and small-metro markets favor PPO's simpler administration, or because Sanford and Avera's dominant local footprint made a tight HMO network harder to differentiate, isn't something CMS's data can answer — but the effect on your options is the same either way.

The two places HMO structure does show up locally

The county isn't 100% PPO end to end — it's 100% PPO for the plans open to a general Medicare beneficiary. The exception is Sanford Health's Great Plains Medicare Advantage and Great Plains Medicare Advantage Gold, both built as HMO Institutional Special Needs Plans. An I-SNP is restricted by CMS rule to people who need a nursing-home level of care — typically because they already live in one. CMS lists both as too new to carry a star rating yet. If you or a family member is in that specific situation, the HMO structure is a real, current option in Minnehaha County. For anyone else, it's not on the table. Our I-SNP guide covers those two plans in full.

Special Needs Plans: why dual-eligible and nursing-home plans chose different structures

It's easy to assume every "Special Needs Plan" works the same way, since they all target a narrower slice of the Medicare population. Minnehaha County's roster shows that isn't true. The county's four Dual-Eligible Special Needs Plans (D-SNPs) — two from UnitedHealthcare and two from Aetna/CVS — are built as PPOs, just like the five standard plans. Every D-SNP here carries the same $41.5 premium, covered in full by Medicare's Low-Income Premium Subsidy for people who qualify for both Medicare and Medicaid, and is marked "coordination-only," meaning it coordinates your Medicare and Medicaid benefits rather than adding new state-level coverage on top. UnitedHealthcare's two D-SNPs carry the county's highest star rating at 4.5★ overall.

The two Institutional Special Needs Plans (I-SNPs), by contrast, are built as HMOs. That's not an accident — an I-SNP serves people who already live in a nursing facility and typically receive most of their care from a tight circle of providers connected to that facility, so a narrower HMO network fits the population it's designed for. A D-SNP member, by comparison, is usually still living independently or with family and needs the same flexibility to see outside specialists that a standard Medicare beneficiary does — which is likely part of why carriers chose the PPO structure for those plans instead. The lesson: "Special Needs Plan" tells you who qualifies, not what network structure you'll get. Always check the specific plan.

What it means if you split time outside Sioux Falls

A lot of Minnehaha County Medicare beneficiaries spend part of the year somewhere else — a winter in Arizona, a summer at a lake place in Minnesota, months at a grandchild's house in another state. This is one of the clearest practical payoffs of the local PPO pattern. With an HMO, care outside the plan's service area is generally limited to true emergencies; a routine visit to a doctor while you're away usually isn't covered at all. With a PPO, you can see an out-of-network provider anywhere in the country that's willing to bill the plan, though you'll pay the plan's out-of-network cost-share rather than the in-network rate. It's not the same as Original Medicare's no-network model, but it's real flexibility an HMO wouldn't give you. If travel is a bigger part of your year, our snowbird coverage guide walks through the specifics plan by plan.

What this means for your specific doctor

Because every standard plan here is a PPO, none of the 5 require a referral before you see a specialist — you can go straight to a cardiologist or an orthopedist covered by the plan. That's a genuine convenience. It does not mean network doesn't matter. A PPO still has a network, and staying inside it is still cheaper than going outside it; you're just not blocked from going outside it the way an HMO would block you. Sioux Falls runs on two competing health systems, Sanford and Avera, and Sanford Health also happens to be the carrier behind the Align PPO plans. Confirming your specific doctor and hospital are in a plan's 2026 network — not just assuming "PPO" means universal access — is still the single most important step before you enroll. Our turning-65 roadmap walks through that network check in more detail.

Does PPO structure cost more here?

Nationally, PPOs often carry a higher average premium than HMOs, because the extra flexibility isn't free for the carrier to offer. That's not the pattern in Minnehaha County. Two of the five standard PPOs — Aetna Medicare Signature and Sanford's Align ChoicePlus — carry a $0 monthly premium for 2026, and Align's drug deductible is $350 versus $615 for some of the others. All five sit at the same 3.5★ CMS rating. In other words, once every plan in your market is a PPO, "PPO" stops being the variable that explains price differences — carrier, deductible, and specific benefit design are what actually separate one plan's cost from another's.

Source: CMS Medicare Monthly Enrollment by County (2026) and CMS Medicare Advantage / Part D Landscape (PY2026), PY2026.

A worked example: three plans, same network freedom, different math

Say you're comparing three of the five standard PPOs: Aetna Medicare Signature, Sanford's Align ChoicePlus, and Wellmark Blue Medicare Advantage Enhanced. All three let you see a specialist without a referral, and all three will pay toward an out-of-network visit if you ever need one — the PPO structure is identical across all three. What isn't identical:

• Aetna Medicare Signature — $0 premium, $615 drug deductible, 3.5★.
• Align ChoicePlus (Sanford) — $0 premium, $350 drug deductible, 3.5★.
• Blue Medicare Advantage Enhanced (Wellmark) — $80 monthly premium, $300 drug deductible, 3.5★.

Two carry no premium at all, and between those two, Align's $350 deductible beats Aetna's $615 by $265 before your drug coverage even kicks in for the year — a real difference for someone on multiple maintenance medications. Wellmark's $80 premium buys a slightly lower $300 deductible, but at $960 a year in premium, it would need a specific formulary or network advantage to be worth the extra cost over the two $0-premium options. None of that math has anything to do with HMO versus PPO — it's carrier, deductible, and your own prescription list, exactly the point this whole article is making.

How to verify a plan's network type yourself before you enroll

Don't take our word, or any brochure's word, for a plan's structure — CMS makes this checkable in a few minutes:

1. Use Medicare's own Plan Finder at Medicare.gov, enter your ZIP code, and open a specific plan's details — the plan type (HMO, PPO, HMO-POS, PFFS, or Cost) is listed near the top, not buried in fine print.
2. Read the plan's Summary of Benefits, which every carrier must publish and which states the network rules and referral requirement in plain language.
3. Call the number on the plan's own materials and ask directly: "Do I need a referral to see a specialist, and is any out-of-network care covered?" A real answer to that one question tells you the network type without needing the jargon at all.
4. Check the plan's Evidence of Coverage if you're already enrolled — it will spell out exactly what happens if you go outside the network.

Our embedded plan finder below pulls the same public CMS data for any Sioux Falls-area ZIP code, so you can see the current-year plan count and structure without digging through a PDF.

The one plan type that isn't HMO or PPO at all

Four of the county's 15 plans — Medica's Prime Solution lineup — are Medicare Cost plans, a different federal product from Medicare Advantage entirely. A Cost plan lets you use its network for lower cost-sharing, but if you go outside it, Original Medicare simply pays its share the way it always would, rather than the visit going uncovered the way it could with an HMO. That's neither the HMO restriction nor the PPO out-of-network cost-share — it's its own hybrid, and it's part of why we listed "Cost plan" as its own category in the roster table above rather than forcing it into the HMO/PPO frame.

How to actually compare these 5 plans

Since the HMO-versus-PPO question is already settled locally, here's what's left to check, in order:

1. Confirm your doctors and hospital are in-network for the specific 2026 plan you're considering — PPO still has a network, even without the HMO lock-in.
2. Run your exact drug list against each plan's formulary and tier structure. Two plans at the same premium can price your specific prescriptions very differently.
3. Compare the deductible — Sanford's Align ChoicePlus carries a lower $350 drug deductible than the $615 several others charge.
4. Check the CMS star rating each year — it's a neutral, published stability signal, not a marketing claim.
5. Decide if you'd ever want an out-of-network provider — a PPO gives you that option; confirm you understand the added cost-share if you use it.

Where PFFS fits in, and why it's mostly gone

You may still see the term PFFS — Private Fee-for-Service — mentioned in older Medicare guides. It's the third classic Medicare Advantage structure alongside HMO and PPO: any Medicare-approved provider willing to accept the plan's payment terms can treat you, with no network and no referral required at all. It sounds like the most open option on paper, but nationally PFFS enrollment has shrunk to a small fraction of the Medicare Advantage market as CMS network-adequacy rules made it harder for insurers to rely on providers simply agreeing case by case rather than joining a contracted network. Minnehaha County has no PFFS plan on its 2026 roster. If you see the term used to describe a plan you're offered, treat it as a signal to ask extra-careful questions about which providers actually participate, since "any provider who agrees" in practice can mean fewer providers agree than you'd expect.

How we help

Big Sioux Benefits compares the plans we offer in the Sioux Falls area against your specific doctors, prescriptions, and budget — at no cost to you, since carriers pay the agent, not you. We won't tell you a plan is "the best." We'll show you where the five standard options actually differ, and where they don't. If you're an adult child sorting this out for a parent in Brandon, Harrisburg, or Tea, we're glad to include you in that conversation directly — Medicare paperwork was never designed to be read alone.

What to watch heading into the 2027 Annual Enrollment Period

1. Re-check plan types every year — a carrier could file an HMO or a hybrid HMO-POS product for a future plan year; don't assume 2026's PPO-only pattern is permanent.
2. Watch your Annual Notice of Change for any shift in network size or referral rules, even within a PPO.
3. Confirm your doctors again before the Annual Enrollment Period closes — networks can narrow year to year even without a plan-type change.
4. Track the national HMO/PPO mix if you or a family member splits time in another state; the plan-type landscape you're used to here may not match there.
5. Ask directly whenever a plan's marketing doesn't specify HMO or PPO — the difference is worth the one extra question.

How we know all this: Big Sioux Benefits runs every article through a data desk that cross-references the CMS Medicare Advantage/Part D landscape file, CMS county enrollment data, and KFF's published analysis of that same CMS data, built by Strategic AI Architects. Every figure here is from a public federal dataset or KFF's own reporting on it. This is education, not advice; confirm your plan's current network and rules with a licensed agent or Medicare.gov. We do not offer every plan available in your area, and any information we provide is limited to the plans we do offer; contact Medicare.gov, 1-800-MEDICARE, or your local SHIP for information on all of your options. We take no payment from any carrier to feature a plan.