Medicare Advantage: How Is It Funded?

Medicare Advantage (aka “MA,” “Part C,” and “the reason your mailbox is full of glossy brochures”) can feel like a
magic trick: $0 premiums, dental, vision, hearing, gym memberships, sometimes even rides to appointments… and yet it’s
still “Medicare.” So where does the money actually come from?

Spoiler: there’s no secret billionaire fairy sprinkling extra benefits on seniors. Medicare Advantage is funded by the
same big Medicare financing streams that pay for Original Medicarethen routed through a very specific payment system
where private plans bid, CMS sets benchmarks, health status is “risk adjusted,” and quality ratings can boost payments.
Understanding that flow makes the marketing make more sense (and helps you spot when a deal is real versus just cleverly
subsidized).

First, what Medicare Advantage is (and what it isn’t)

Medicare Advantage plans are private health plans that contract with the Centers for Medicare & Medicaid Services (CMS)
to provide Medicare-covered services. Instead of the government paying doctors and hospitals directly under Original Medicare,
Medicare pays a private plan a monthly amount for each enrolled person, and the plan pays providers (and manages networks,
prior authorization, and extra benefits).

Important reality check: Medicare Advantage is not “private insurance replacing Medicare.” It’s Medicare dollars administered
through private insurers under federal rules. The funding still starts with Medicare.

Where the money starts: Medicare’s two big trust funds

Medicare isn’t financed from one giant pot. It’s mainly funded through two trust fund accounts held by the U.S. Treasury:

1) The Hospital Insurance (HI) Trust Fund (mostly Part A)

The HI Trust Fund funds Medicare Part A (inpatient hospital care, skilled nursing facility care, hospice, certain home health
services) and related administration. The major revenue source is payroll taxes (plus smaller streams like taxes on Social Security
benefits, interest on trust fund investments, and Part A premiums paid by people who don’t qualify for premium-free Part A).

2) The Supplementary Medical Insurance (SMI) Trust Fund (Parts B and D)

The SMI Trust Fund funds Part B (doctor visits, outpatient care, preventive services, etc.) and Part D (prescription drugs), plus
administration. Its key funding sources are (a) funds authorized by Congress (general revenue transfers) and (b) premiums paid by
people enrolled in Part B and Part D (including income-related adjustments for higher-income beneficiaries).

Here’s the key for Medicare Advantage: Part C is not “separately financed.” Instead, MA spending is funded proportionately from
the HI and SMI trust funds based on whether the plan is providing Part A-type or Part B-type services (and Part D is funded through SMI).
Translation: Medicare Advantage is largely funded by payroll taxes, general revenues, and beneficiary premiumschanneled through a plan.

How Medicare pays Medicare Advantage plans: the “bid + benchmark” engine

Medicare Advantage funding is less like “here’s a pile of cash, good luck!” and more like “tell us what you’ll charge, and we’ll pay
based on a county target plus adjustments.” Every year, plans submit bids to CMS, and CMS sets payment benchmarks by county.

Step 1: CMS sets a county benchmark (the target amount)

A benchmark is basically “what Medicare expects it would spend per beneficiary in Original Medicare in this county,” with adjustments.
Under statute, county benchmarks vary by quartile and are set as a percentage of projected fee-for-service (FFS) spendingcommonly
95%, 100%, 107.5%, or 115% depending on the county’s relative FFS costs. (Counterintuitive but true: higher-cost counties often get
a lower percentage, and lower-cost counties can get a higher percentage.)

Benchmarks are also affected by quality bonuses tied to the Medicare Advantage Star Ratings system. Higher-rated contracts can have a
bonus amount added to benchmarks, and certain “double bonus” counties can receive larger benchmark boosts. The benchmark, in other words,
is not just “FFS spending”it’s “FFS spending filtered through policy and quality incentives.”

Step 2: The plan submits its bid (its estimated cost for Part A & B benefits)

Plans submit a bid estimating what it will cost them to provide Medicare Part A and Part B benefits for an average enrollee. This bid is
not the same as what you pay; it’s what the plan says it needs to cover Medicare-covered services (before your copays, deductibles, and
before any extra benefits).

Step 3: CMS compares bid vs. benchmarkand that decides the payment structure

If the bid is below the benchmark

This is the most common scenario. When a plan bids below the benchmark, Medicare pays the plan:

• A base payment roughly equal to the plan’s bid (for Part A & B benefits), and
• A “rebate”a percentage of the difference between the benchmark and the plan’s bid.
  The rebate percentage is tied to the plan’s Star Rating (commonly 50%, 65%, or 70%).

The rebate is the not-so-secret sauce behind “extra benefits.” Plans must use rebate dollars to fund supplemental benefits or reduce costs
for enrolleesthings like benefits not covered under Parts A/B, reduced cost sharing for Part A/B services, reduced Part D cost sharing,
or even lowering the Part B or Part D premium. If a plan wants to offer extras that cost more than the rebate, it canbut then it typically
needs to charge an additional premium.

If the bid is at or above the benchmark

When a plan bids above the benchmark, Medicare generally pays up to the benchmark amount, and the enrollee owes an additional plan premium
equal to the difference. In plain English: if the plan is expensive relative to the county target, you may see a monthly premium on top of
your Part B premium.

Risk adjustment: why your diagnosis codes matter to the math

If Medicare paid every plan the same flat amount per person, plans would have a strong incentive to enroll healthier people and avoid sicker
ones. Risk adjustment is supposed to reduce that incentive by paying more for enrollees who are expected to cost more.

CMS-HCC risk scores (a quick, human-friendly version)

CMS uses a risk adjustment model (the CMS-HCC model) that considers demographics (age, sex), and documented health conditions (diagnoses)
to assign each enrollee a risk score. A risk score around 1.0 is roughly “average expected cost.” Higher than 1.0 means the person is expected
to cost more; lower than 1.0 means less.

Then Medicare adjusts the plan’s base payment based on that score. So the “bid vs. benchmark” comparison happens, and then the payment gets
scaled for the enrollee’s expected health care needs.

The coding intensity problem (and the built-in haircut)

Risk adjustment depends on diagnosis codes, which creates a strong incentive for plans to document as many conditions as possible. Policymakers
have long noted that diagnoses tend to be coded more intensely in MA than in Original Medicare, which can increase payments.

Federal law requires CMS to apply an MA coding pattern adjustmentan automatic reduction to risk scores (not less than 5.9%) to account for
differences in coding patterns between MA and traditional Medicare. CMS also updates the risk model over time (for example, through newer
versions such as the phased-in transition to “V28”) to better align payments with true risk and reduce incentives to over-code.

Quality Bonus Payments: when stars turn into dollars

Star Ratings don’t just help beneficiaries compare plans; they also affect funding. Under the Quality Bonus Program, plans (technically, contracts)
with higher ratings can receive benchmark increases. That larger benchmark can increase Medicare payments and also increase the rebate amount a plan
can use for extra benefits or lower premiums.

In practice, quality bonuses have become a meaningful slice of MA funding. Analysts have estimated bonus payments in the tens of billions annually in
recent years, and a large share of MA enrollees are in plans receiving a quality bonus. This is one reason MA benchmarks can grow faster than FFS
spending: bonuses raise the ceiling.

What about prescription drugs in Medicare Advantage (MA-PD plans)?

Many Medicare Advantage plans include Part D drug coverage (these are called MA-PDs). Funding for the drug portion runs through Part D financing rules
(and the SMI trust fund), which can include:

• Direct subsidies from Medicare to help cover the plan’s drug benefit costs,
• Reinsurance/subsidies tied to higher-cost beneficiaries,
• Low-income subsidies (for beneficiaries who qualify), and
• Beneficiary premiums (including income-related adjustments for higher-income enrollees).

Part D policy has been evolving in recent years (including redesign elements tied to the Inflation Reduction Act), which affects how risk is shared and
how subsidies flow. If you’re comparing MA-PD plans, remember: the drug benefit funding has its own rules layered on top of the Part A/B payment system.

What beneficiaries pay: “$0 premium” doesn’t mean “$0 funded”

A common misconception is that a $0-premium Medicare Advantage plan is “free.” It’s more accurate to say: “The plan premium might be $0, but the plan
is still fundedmostly by Medicare.”

Most Medicare Advantage enrollees still pay:

• The Part B premium (this is a big funding stream for Medicare overall and continues regardless of MA enrollment),
• Cost sharing (copays/coinsurance/deductibles) based on the plan’s benefit design, and
• Sometimes an additional plan premium if the bid is above the benchmark or if extras cost more than rebates cover.

A simple example (numbers rounded for sanity)

Imagine County A has a benchmark of $1,000/month for Part A/B services.
A plan bids $900/month. The difference is $100.
If the plan qualifies for a 70% rebate rate (often associated with higher Star Ratings), the rebate is $70.

Medicare’s payment to the plan (before risk adjustment) is roughly $900 + $70 = $970/month.
If an enrollee has a risk score of 1.20, the risk-adjusted payment becomes higher (conceptually scaling that base payment).
The plan then uses the rebate dollars to offer extrasmaybe dental/vision, maybe lower copays, maybe even a Part B “giveback” in some markets.
Your premium can be $0 even though Medicare is paying the plan close to a thousand dollars a month (or more) for your coverage.

Where “extra benefits” really come from

Extra benefits are funded mainly through:

• Rebate dollars (from bid-below-benchmark savings),
• Quality bonus-related benchmark increases (which can increase rebates),
• Efficiency strategies (negotiated provider rates, care management, narrower networks), and
• Sometimes enrollee premiums for richer packages.

This is why MA can look like a bargain at the point of sale: the plan can “spend” rebate dollars on benefits you notice (dental, OTC cards, gym)
while relying on Medicare’s base payments for the expensive stuff (hospitalizations, imaging, chronic care).

Guardrails and oversight: it’s not a blank check

Medical Loss Ratio (MLR): the 85% rule

Medicare Advantage (and Part D) contracts are subject to a minimum Medical Loss Ratio requirement: plans generally must spend at least 85%
of revenue on medical claims and quality improvement (not on admin and profit). Contracts that fail the minimum MLR can face financial remittances and other
sanctions, escalating over time.

Risk adjustment audits (RADV) and improper payments

Because risk adjustment depends on diagnoses, CMS runs risk adjustment data validation (RADV) audits to confirm diagnoses submitted for payment are supported
by medical records. If diagnoses are unsupported, CMS can collect overpayments. The HHS Office of Inspector General (OIG) has also repeatedly examined whether
diagnoses used for risk adjustment are adequately documented, noting that unsupported diagnoses can drive improper payments.

The big debate: does Medicare pay “too much” for Medicare Advantage?

Medicare Advantage is popular, and many beneficiaries value the out-of-pocket maximum and extra benefits. But MA funding is also one of the loudest budget
debates in Medicare policy.

Analysts and policymakers point to several factors that can push Medicare Advantage spending above what Medicare would have spent in Original Medicare for
similar beneficiaries:

• Benchmarks above FFS spending in many areas (especially in lower-cost counties with higher benchmark percentages),
• Quality bonuses that raise benchmarks and rebates,
• Coding intensity (more diagnoses documented can increase risk scores and payments, even with the statutory coding adjustment),
• Favorable selection (if healthier beneficiaries are more likely to enroll or remain in MA), and
• Complex plan behavior (plans may adjust bids strategically based on benchmark rules).

MedPAC has published comparisons of MA payments vs. FFS spending and has updated its estimates over time as methods and models change. More recent analyses
also emphasize that model updates (like risk model revisions and adjustments related to coding intensity) can shift these estimates. Meanwhile, CMS continues
to refine payment rules through the annual Advance Notice and Rate Announcement process.

Why does this matter to you, the human with a real pharmacy receipt? Because if MA payments rise as a share of Part A and Part B spending, that can affect
trust fund balances and Part B premiums over time. Medicare Advantage funding debates aren’t just inside-the-Beltway sport; they can influence premiums, plan
generosity, and oversight rules.

Follow the dollar: a plain-English funding map

1. Money flows into Medicare via payroll taxes (HI), general revenue + premiums (SMI), and other smaller sources.
2. CMS sets county benchmarks based on projected FFS spending and policy adjustments (including quality bonus rules).
3. Plans submit bids estimating their cost to provide Part A & B services.
4. CMS calculates base payments using the bid/benchmark relationship, plus rebates when bids are below benchmarks.
5. Payments are risk adjusted using CMS-HCC risk scores (with statutory coding pattern adjustments applied).
6. Plans use rebates to fund supplemental benefits or reduce premiums/cost-sharing (within federal rules).
7. Beneficiaries pay their part (Part B premium, cost sharing, and sometimes a plan premium).
8. Oversight happens (MLR requirements, audits, compliance rules, and periodic payment model updates).

FAQ: quick answers people actually ask

Is Medicare Advantage funded by taxpayers?

Largely, yesthrough the same Medicare financing streams that fund Original Medicare: payroll taxes, general revenues authorized by Congress, and beneficiary premiums.
Medicare Advantage just routes those funds through private plans rather than paying providers directly.

Do $0-premium MA plans cost Medicare $0?

Definitely not. A $0 plan premium usually means the plan is using rebate dollars (and sometimes other strategies) to reduce what you pay monthly. Medicare is still
making monthly payments to the plan for your coverage.

Why do plans advertise dental and vision so aggressively?

Because those benefits are highly visible and relatively predictable in cost. Rebate dollars can be packaged into benefits that feel tangible and competitive, even if
the big spending drivers are hospital and chronic care costs that you don’t see until something goes wrong.

Does a higher Star Rating mean the plan is “better funded”?

Often, yes. Higher ratings can increase benchmarks and rebate percentages, giving plans more room to fund extras or lower premiums. But Star Ratings are complicated
and reported at the contract level, so it’s smart to look at provider networks and drug coverage details too.

What’s the catch?

Not always a “catch,” but there are tradeoffs: many plans use networks, utilization management, and prior authorization to control costs. The funding model rewards plans
for bidding below benchmarks and managing riskso they have strong incentives to control spending and document diagnoses thoroughly.

Real-world experiences: what Medicare Advantage funding feels like on the ground (about )

Funding formulas can sound abstract until you live with them. People often experience Medicare Advantage financing in a few predictable, very human waysusually while
holding a cup of coffee and an “Annual Notice of Change” letter they didn’t ask for.

1) “My plan is $0, but why am I still paying every month?”
A classic first-year surprise is realizing the Part B premium doesn’t disappear when you join Medicare Advantage. Many beneficiaries mentally file MA as “one plan,”
while Medicare treats it as “Part B premium still applies, plus a plan that replaces Original Medicare’s payment method.” Some plans even market a Part B premium
reduction (“giveback”)which is basically the funding model showing off: the plan uses part of its rebate to reduce what you pay for Part B.

2) The “extra benefits carousel.”
Many enrollees love the extrasdental cleanings, eyewear allowances, hearing aid support, OTC credits. But people also notice that these benefits can change from year
to year. That’s not necessarily chaos; it’s the bid/benchmark/rebate system in motion. If the plan’s projected costs, benchmark, or rebate situation changes, the plan
may adjust extras, copays, or networks to stay competitive and profitable (and to meet the 85% MLR rule).

3) Networks and prior authorization: the quiet side of “how we afford this.”
Extra benefits don’t fund themselves. Many plans control spending through negotiated provider rates, narrower networks, and utilization management. A beneficiary might
feel this when a specialist is “out of network,” a preferred hospital system changes, or a service requires prior authorization. Those strategies are often how plans
keep bids low enough to generate rebates that fund the flashy benefits.

4) The paperwork that follows diagnoses.
People sometimes notice more frequent health assessments, chart reviews, or reminders to “complete your annual wellness visit.” Some of that is good preventive care.
Some of it also reflects risk adjustment incentives: documented conditions can affect payments. The oversight side of the system shows up here tooplans know that
diagnoses used for risk adjustment are subject to audit and must be supported by medical records.

5) Plan shopping becomes an annual ritual (like taxes, but with more acronyms).
Because MA funding is recalculated annuallybenchmarks, bids, risk model updates, Star Ratingsplans can change premiums, drug formularies, and benefits each year.
Many experienced beneficiaries treat open enrollment as a yearly “benefit checkup”: confirm doctors are still in-network, confirm prescriptions are still covered at a
reasonable tier, and read the out-of-pocket maximum like it’s the season finale of a drama.

The biggest takeaway from these lived experiences is simple: Medicare Advantage funding is dynamic. It’s designed to reward competitive bidding, adjust for health
status, and incentivize quality. When it works well, it can translate into lower premiums and useful extras. When it’s strainedor when incentives are misalignedit can
show up as tighter networks, more utilization management, and frequent plan changes. Knowing the funding mechanics helps you interpret what you’re seeing, not just what
you’re being sold.