ACA Marketplace Plans

Health insurance that individuals and families buy for themselves through the government-run exchanges created by the The Affordable Care Act (ACA) — not through an employer, not through Medicare, not through Medicaid. These are private plans, sold by private insurers, but priced, subsidized and standardized by federal rules.

How it works

A consumer applies during the annual Open Enrollment window (roughly November to mid-January) or after a qualifying life event (a "Special Enrollment Period"). They report household income, and the exchange determines eligibility for financial help in real time.

Plans are sold as Qualified Health Plans (QHPs) and sorted into four metal tiers by actuarial value (AV) which is the share of total covered medical costs the plan is expected to pay across a standard population:

• Bronze — ~60% AV. Lowest premium, highest cost sharing.
• Silver — ~70% AV. The pivotal tier (see subsidies below).
• Gold — ~80% AV.
• Platinum — ~90% AV. Highest premium, lowest cost sharing.

AV is not a guarantee for any one person. Rather it's the average across a standard population. A high deductible can sit behind a "60%" plan. Every QHP also caps annual out-of-pocket spending. In 2026 it's $10,600 for an individual and $21,200 for a family.

Subsidies: APTC and CSR

Two distinct subsidies make Marketplace coverage affordable, and they are conflated constantly.

The Advance Premium Tax Credit (APTC) lowers the monthly premium. It is pegged to the second-lowest-cost Silver plan in your area (the "benchmark"). The credit equals the gap between that benchmark premium and a capped percentage of your income so the benchmark is effectively free or near-free at lower incomes. Apply it to a cheaper Bronze plan and you pocket the difference; apply it to a richer Gold plan and you pay the spread. It's "advance" because it's paid to the insurer monthly and reconciled on your tax return.

Cost-Sharing Reductions (CSR) are the second subsidy, and they only work on Silver plans. For lower-income enrollees, CSR silently upgrades a 70% Silver plan to a richer variant — 94% AV (100–150% of the federal poverty level), 87% (150–200%), or 73% (200–250%). Same network, same premium, far lower deductibles and copays. This is why "buy Silver if you qualify for CSR" is the single most important piece of Marketplace advice.

Under the law's baseline rules, APTC requires household income between 100% and 400% of the federal poverty level (FPL). The American Rescue Plan Act (2021), extended by the Inflation Reduction Act through 2025, made the credits enhanced: it removed the 400% FPL cliff and capped premium contributions at 8.5% of income. Those enhanced credits expired at the end of 2025 absent further congressional action.

Risk adjustment and reinsurance

Because insurers must accept all comers and can't price on health status, a plan that happens to enroll sicker members would be punished for it. Two mechanisms blunt that.

Risk adjustment (ACA 1343, run by CMS (Centers for Medicare & Medicaid Services)) is permanent and budget-neutral: within each state market, plans with healthier-than-average enrollees pay into a pool, and plans with sicker-than-average enrollees draw from it. Ths is one mechanism aimed at balancing the unequal distribution of sicker members. Transfers are computed from members' HCC risk scores and a statewide average premium. No federal money is added so it's a zero-sum reshuffle that removes the incentive to cherry-pick healthy members.

Reinsurance was originally a temporary federal "3 Rs" program (2014–2016) that reimbursed plans for very high-cost individual claims. It has since migrated to the state level and many run their own reinsurance pools via Section 1332 State Innovation Waivers, which have measurably lowered premiums in those states.

Essential health benefits

Every non-grandfathered individual and small-group plan must cover ten Essential Health Benefit (EHB) categories (ACA 1302): ambulatory care; emergency services; hospitalization; maternity and newborn care; mental health and substance-use disorder services; prescription drugs; rehabilitative and habilitative services; laboratory services; preventive/wellness and chronic-disease management; and pediatric services including oral and vision. EHBs are why Marketplace plans can't sell a stripped-down "hospital-only" product, and why benefit design is far more standardized here than in self-funded employer plans, which are exempt from EHB rules under ERISA.

Who is involved

Insurers file plans and rates with state regulators and CMS. Brokers and "Navigators" help people enroll. Members choose and pay. CMS and state DOIs review filings, run risk adjustment, and operate the exchanges. The Medical Loss Ratio (MLR) floor (80% for the individual market) caps insurer overhead and profit.

Numbers that matter

• Metal tier AVs: 60 / 70 / 80 / 90%. CSR Silver variants: 73 / 87 / 94%.
• APTC income band (baseline): 100–400% FPL. Enhanced cap: 8.5% of income, expired end-2025.
• 2026 out-of-pocket max: $10,600 individual / $21,200 family.
• Peak enrollment: 24.3M (2025); ~1.5M decline for 2026.
• Individual-market MLR floor: 80%.

Related

• The Stakeholders
• The Affordable Care Act (ACA)
• Payers (Health Plans)
• Commercial & Employer-Sponsored Insurance
• Medicaid & Managed Medicaid
• Cost Sharing
• Eligibility & Enrollment
• Risk Adjustment & HCC Coding
• Medical Loss Ratio (MLR)
• Benefit Design & the SBC
• Plan Types (HMO, PPO, EPO, POS, HDHP)
• CMS (Centers for Medicare & Medicaid Services)

Sources

• Essential health benefits, ACA §1302 — eCFR 45 CFR Part 156
• HHS Notice of Benefit and Payment Parameters for 2026 — Federal Register
• Premium Tax Credit and Cost-Sharing Reductions — CRS R44425
• Enhanced Premium Tax Credit and 2026 Exchange Premiums — CRS R48290
• ACA Risk Adjustment Program FAQ — CRS R45334
• Enrollment Growth in the ACA Marketplaces — KFF
• What We Know So Far About 2026 ACA Marketplace Enrollment, Premiums, and Deductibles — KFF