Newsroom · Sioux Falls

Medicare Annual Enrollment Period in Sioux Falls 2026: your Oct 15–Dec 7 action plan

AEP is the one window each year when you can rethink your whole Medicare picture — here's what to review, what changed in 2026, and what the Sioux Falls plan landscape actually looks like.

Medicare ATX Data Desk

Published June 16, 2026 · 10 min read · Sourced from CMS.gov

The Medicare Annual Enrollment Period (AEP), which runs October 15 through December 7 each year, is the one time every Medicare beneficiary can freely switch plans — and in 2026, there are real reasons to look. The Part D out-of-pocket cap is new. Plan networks and formularies shift every year. And in Sioux Falls, the Sanford-vs-Avera network dynamic means the wrong plan can put your own doctors out of reach.

Every figure below comes from public federal data: the CMS PY2026 plan landscape, CMS star ratings, CMS Hospital Compare, and CDC PLACES local health data. No invented numbers.

What AEP is — and what it isn't

Medicare has several enrollment windows, and they're not interchangeable. AEP is the most powerful, but it has a twin — the Open Enrollment Period — and a wildcard: Special Enrollment Periods triggered by life events.

Source: CMS Medicare enrollment rules; CMS Medicare Advantage / Part D Landscape (PY2026).

The key distinction: AEP lets you make any coverage change from scratch. OEP (Jan 1–Mar 31) allows only one MA-to-MA switch or a drop back to Original Medicare — you cannot use OEP to add a stand-alone Part D plan if you're in Original Medicare. And OEP doesn't reset your Medigap rights: outside your original 6-month guarantee-issue window, South Dakota insurers can require medical underwriting for a supplement.

Who should actively shop during AEP

You don't have to switch every year — but you should look every year. The following situations are strong signals to review your plan against what's available:

• Your ANOC shows a formulary change. If a drug moved to a higher tier or was removed, your out-of-pocket drug cost may have jumped even if the premium stayed flat.
• Your doctor changed affiliation. In Sioux Falls, physicians sometimes move between the Sanford and Avera systems — a change that can flip your in-network status overnight.
• Your plan's star rating dropped. A plan that dips below 3 stars for multiple consecutive years can be terminated by CMS. Checking the rating each fall is your early-warning system.
• You're newly eligible for Medicaid. If your income dropped and you now qualify for both Medicare and Medicaid (dual-eligible), a D-SNP plan may provide far richer benefits — including $0 cost-sharing — that a standard MA plan won't match.
• You want to switch from Advantage to Original Medicare. AEP is the most reliable window. Remember: Medigap may require medical underwriting if you're past your original open-enrollment period.

The 2026 Sioux Falls plan landscape you're choosing from

Minnehaha County is South Dakota's largest Medicare market, with 39,532 enrolled beneficiaries — more than any other county in the state. Despite that size, the plan menu is deliberately focused: no HMO-style gatekeeping, all standard plans are PPOs, and two plans carry $0 monthly premiums. Here are the 5 standard Medicare Advantage PPOs open to any beneficiary during AEP:

Source: CMS Medicare Advantage / Part D Landscape (PY2026) & CMS Medicare Advantage & Part D Star Ratings (2026), Minnehaha County, 2026.

All five plans hold a 3.5★ CMS rating — the average tier. None are flagged for termination risk, but none have earned the 4★+ that triggers CMS quality bonuses. For AEP shoppers, this means the comparison comes down to network fit, drug formulary, and the out-of-pocket maximum rather than a star-rating standout.

The 2026 Part D cap: why drug coverage matters more now

The biggest structural change for 2026 is a federal cap on out-of-pocket prescription drug spending under Part D. Once your yearly drug costs reach the ceiling, your plan pays 100% for the rest of the year.

Source: CMS 2026 Part D benefit parameters; CMS Medicare Advantage / Part D Landscape (PY2026).

Before 2026, beneficiaries with high drug costs could face an open-ended "coverage gap" (the donut hole). That structure is gone. But the cap only protects you if you're enrolled in a creditable Part D plan in the first place — either built into a Medicare Advantage plan or as a stand-alone PDP alongside Original Medicare. If you have no creditable drug coverage, the cap does nothing for you.

During AEP, run your specific medication list through each plan's formulary: what tier is each drug on, what's the copay before and after the deductible? The $2,100 ceiling changes the math — a plan with a higher premium but favorable tier placement for your most expensive drug can cost far less over the full year than a $0-premium plan that places the same drug at Tier 4.

The Sanford-vs-Avera network question at AEP time

Every fall in Sioux Falls, the network question comes back. The city's care runs through two competing health systems — Sanford Health and Avera Health — and a plan's provider network is the bridge between you and your doctors.

Source: CMS Hospital Compare — Overall Star Ratings.

Sanford USD Medical Center holds a 5-star CMS overall rating; Avera McKennan carries a 4-star. Both are strong. The wrinkle: Sanford backs its own Medicare plans through the Align brand (Align ChoicePlus and ChoiceElite), so those plans naturally favor the Sanford network. If your PCP and specialists are on the Avera side, that matters — out-of-network PPO costs are higher, and some services may require a prior authorization you don't expect.

The actionable step: before AEP ends, look up your specific doctors on each plan's 2026 online directory — not last year's. Network changes don't require advance notice to you beyond the ANOC, and a physician who was in-network last year may not be in 2027.

How to read your Annual Notice of Change

Your insurer must mail an ANOC by September 30 each year. It's the most important piece of pre-AEP mail you'll receive. Here's what to look for:

1. Premium and cost-sharing changes. Page 1 usually shows the new monthly premium, deductible, and copay structure. A small premium increase can be swamped by a copay change if you use specialist care frequently.
2. Formulary (drug list) changes. Scan for any of your drugs. If a medication moved from Tier 2 to Tier 3 or Tier 4, your annual cost for that drug may have increased by hundreds of dollars even if nothing else changed.
3. Network changes. The ANOC will note if major provider groups or hospitals left or joined the network. For Sioux Falls, any change to Sanford or Avera participation is the headline item.
4. Out-of-pocket maximum changes. With the 2026 Part D cap at $2,100, confirm whether your plan's combined medical + drug out-of-pocket maximum changed year over year.
5. Extra-benefit changes. Dental, vision, and hearing coverage is not standardized across MA plans — it can be reduced or eliminated each year. If you rely on any supplemental benefit, verify it's still in the 2027 plan year.

Local health context: what Sioux Falls AEP shoppers are managing

Plan choice isn't abstract — it's personal. CDC data on Minnehaha County adults shows the chronic-condition load that shapes which plan benefits matter most here:

Source: CDC PLACES: Local Data for Better Health, County 2023 (2023), Minnehaha County adults.

Nearly a third of county adults manage high blood pressure; more than one in ten has diagnosed diabetes; over a fifth has arthritis. If you're managing one of these conditions, the plan's specialist network, formulary tiers for maintenance medications, and prior-authorization requirements deserve at least as much attention as the monthly premium. AEP is the time to check all three.

What to watch before and during AEP 2026

1. Read your ANOC when it arrives in late September — look specifically at drug tiers and the out-of-pocket maximum before you decide whether to shop.
2. Verify your doctors' network status for 2027 using each plan's online provider directory, not last year's list.
3. Run your full drug list through the formulary tool at Medicare.gov — the $2,100 Part D cap changes the annual-cost math for people with expensive medications.
4. Check each plan's CMS star rating (published each fall before AEP) — a plan below 3.5★ two years running is on CMS's watch list; below 3.0★ three years running, it can be terminated.
5. Don't wait until December 7 — if you want help comparing the plans we offer in the Sioux Falls area, earlier in the window means less scheduling pressure and more time to confirm network details.

How we know all this: Big Sioux Benefits runs every article through a data desk that cross-references the CMS plan landscape, county enrollment, 2026 star ratings, hospital quality data, and CDC health data — built by Strategic AI Architects. Every figure here is from a public federal dataset. This is education, not advice; confirm your plan, costs, and eligibility with a licensed agent or Medicare.gov. We take no payment from any carrier to feature a plan.