Overview: The ACA fundamentally reordered what any plan must cover and how much it can ask policyholders to pay — transforming individual market insurance from a patchwork of exclusions into a standardized floor of coverage.

The 10 Essential Health Benefits

The ACA requires all non-grandfathered individual and small-group health plans to cover services in 10 categories of Essential Health Benefits (EHBs). These categories are:

Ambulatory patient services — outpatient care (doctor visits, urgent care, specialist visits)
Emergency services — ER care, including out-of-network emergencies
Hospitalization — inpatient surgeries, overnight stays, and nursing care
Pregnancy, maternity, and newborn care — prenatal visits, labor and delivery, postnatal care
Mental health and substance use disorder services — therapy, counseling, inpatient psychiatric and addiction treatment; must follow federal mental health parity rules
Prescription drugs — at minimum one drug per USP category and class
Rehabilitative and habilitative services and devices — physical therapy, speech therapy, wheelchairs, braces; importantly, habilitative services (developing skills never had, like a child's speech therapy) were added as an EHB alongside rehabilitative services (regaining lost skills)
Laboratory services — diagnostic blood work, imaging, screenings
Preventive and wellness services and chronic disease management — routine physicals, recommended screenings, vaccinations, chronic disease management
Pediatric services, including oral and vision care — comprehensive children's health, dental exams, annual vision exam, and corrective lenses for children under 19

Important note: Adult dental and vision coverage are not federally required EHBs, even though pediatric dental and vision are.

Before the ACA, the individual market was highly fragmented. Only about 12% of individual plans covered maternity care; mental health benefits were commonly excluded or heavily limited; prescription coverage was inconsistent. The EHB mandate eliminated this category-by-category gap coverage, ensuring every plan provides a complete, usable package.

How the ACA Changed the Cost-Sharing Landscape

The ACA restricted how plans can use deductibles, copayments, and coinsurance in several important ways:

Annual out-of-pocket maximums: All non-grandfathered plans must cap total out-of-pocket costs for EHB services. For 2026, the federal maximums are $10,600 for individual coverage and $21,200 for family coverage. Once a policyholder reaches these limits through any combination of deductible, coinsurance, and copays, the insurer must pay 100% of covered in-network care for the remainder of the year.

Embedded individual OOP maximum in family plans: No single family member can be required to pay more than the individual OOP maximum, even within a family plan that hasn't reached its aggregate family limit. This prevents one sick family member from bearing unlimited costs while others remain healthy.

Zero-cost-sharing preventive services: Recommended preventive services (annual checkups, immunizations, cancer screenings, contraception) must be covered with no deductible, copay, or coinsurance when delivered by in-network providers. This shifted routine wellness from a cost-sharing event to a universally covered benefit.

Prohibition on annual and lifetime dollar limits: Plans cannot cap how much they will pay for EHB services in any year or over the insured's lifetime. This ended the pre-ACA era where patients could "max out" their cancer or ICU coverage mid-treatment.

Metal tier actuarial values: To prevent cheap-premium plans from hiding enormous cost-sharing burdens, the ACA organized plans into standardized tiers based on actuarial value — the average share of costs the plan pays:

Tier	Actuarial Value	Who pays on average
Bronze	~60%	Plan pays 60%, insured pays 40%
Silver	~70%	Plan pays 70%, insured pays 30%
Gold	~80%	Plan pays 80%, insured pays 20%
Platinum	~90%	Plan pays 90%, insured pays 10%

Cost-sharing reductions (CSRs): For individuals earning between 100%–250% of the federal poverty level who enroll in a Silver plan through the Marketplace, federal subsidies reduce deductibles, copayments, and OOP maximums, effectively boosting the plan's actuarial value to as high as 94%.

Large group and self-insured plans: While large employers (generally 51+ employees) and self-funded plans are not required to cover all 10 EHBs, they are still prohibited from imposing lifetime or annual dollar limits on any services they choose to cover that qualify as EHBs under the applicable state benchmark.