The Affordable Care Act marketplace is entering the most turbulent period it has experienced since the near-collapse of insurer participation in 2017–2018. From tracking ACA enrollment data and insurer rate filings over the past several years, we have never seen so many simultaneous pressure points converge on this market in a single plan year. Enhanced premium tax credits have expired, enrollment has declined for the first time since 2020, median premium increases are the steepest in eight years, and major carriers are exiting the exchanges entirely. For health actuaries working in individual market pricing, risk adjustment, or regulatory affairs, 2026 represents a once-in-a-decade inflection point that will reshape risk pools, carrier strategy, and the very economics of exchange-based coverage.
This analysis examines the forces reshaping the ACA marketplace in 2026 through an actuarial lens-digging into enrollment data, premium dynamics, adverse selection mechanisms, insurer profitability signals, and the emerging patchwork of state-level responses that is creating an increasingly fragmented regulatory landscape.
The Enhanced Subsidy Expiration: Anatomy of a Policy Shock
The enhanced premium tax credits (ePTCs), first enacted under the American Rescue Plan Act of 2021 and extended through 2025 by the Inflation Reduction Act, expired on December 31, 2025. This represents the single most consequential affordability change in the ACA’s history since the original premium tax credit structure was established in 2014.
The magnitude of this shift is difficult to overstate. Under the enhanced subsidies, premium contributions were capped at 8.5% of household income across all eligible income levels, with zero-premium benchmark plans available for many low-income enrollees. The enhanced credits also eliminated the so-called “subsidy cliff” that had previously cut off all financial assistance for households earning above 400% of the federal poverty level (FPL).
With expiration, the subsidy structure reverts to the original ACA formula. The required contribution percentages at each income tier increase substantially: households below 150% FPL, which previously paid zero percent of income toward a benchmark plan, now face contributions of up to 4.19% of income in 2026. Households above 400% FPL-approximately $62,600 for an individual or $128,600 for a family of four-lose subsidy eligibility entirely.
KFF estimated that the expiration would more than double average annual premium payments for subsidized enrollees, increasing from $888 in 2025 to $1,904 in 2026-a 114% increase. For specific demographic and income segments, the impact is even more severe. A family of four earning $130,000 (404% FPL) enrolled in benchmark coverage could face an annual premium increase of approximately $11,450-a 104% jump-upon losing all subsidy eligibility, according to analysis by the Center on Budget and Policy Priorities.
Asymmetric Risk Pool Impact
From an actuarial standpoint, what makes this policy change particularly disruptive is its asymmetric effect on the risk pool. The enhanced subsidies had attracted a significantly younger, healthier population into marketplace coverage. When subsidies become less generous, price-sensitive healthy individuals are the first to leave, while those with chronic conditions and higher expected claims costs retain stronger incentives to maintain coverage regardless of premium increases.
Enrollment Decline: The First Contraction Since 2020
The Centers for Medicare & Medicaid Services (CMS) reported that approximately 23 million consumers selected ACA marketplace plans for 2026 coverage, down from 24.2 million in the 2025 open enrollment period-a decline of roughly 1.2 million plan selections, or about 5%. This marks the first year-over-year enrollment decline since 2020, ending a streak of unprecedented growth that had doubled marketplace participation from roughly 11 million in 2020 to a record 24.3 million in 2025.
| Metric | 2025 OEP | 2026 OEP | Change |
|---|---|---|---|
| Total plan selections | ~24.2 million | ~23 million | -5% |
| HealthCare.gov states (30) | ~16.9 million | ~15.8 million | -6.5% |
| State-based exchanges (21) | ~7.3 million | ~7.2 million | -1.4% |
| New enrollees | ~3.9 million | ~3.4 million | -12.8% |
| Returning enrollees | ~20.2 million | ~19.6 million | -3.0% |
Several state-level patterns reveal the distributional effects of subsidy expiration. North Carolina experienced a 22% enrollment decline (from 975,110 to 761,457), Ohio dropped 20% (from 583,443 to 469,616), and West Virginia, Indiana, Delaware, and Arizona all declined by at least 15%. These steep declines are concentrated in HealthCare.gov states that lack supplemental state subsidies.
Notably, Texas bucked the national trend with a 5% enrollment increase, adding approximately 206,000 enrollees to reach 4.17 million. Florida, despite losing nearly 197,000 enrollees year-over-year, remains the single largest marketplace state at 4.54 million. States with their own supplemental subsidy programs-Connecticut, Maryland, Massachusetts, New Jersey, and New Mexico-generally saw enrollment hold steady or grow.
These headline plan selection numbers almost certainly overstate actual 2026 coverage. As KFF has emphasized, plan selections include consumers who were automatically renewed for 2026 but may not have yet received or reacted to their new, higher premium bills. The effectuation rate-the proportion of plan selectors who actually pay premiums and activate coverage-has historically been above 90%, but 2026 will mark the first time most marketplace enrollees face a significant premium increase, making past effectuation rates unreliable benchmarks. CMS typically releases effectuated enrollment data in a summer report, with the early snapshot expected around July 2026.
The Congressional Budget Office (CBO) projected that without a permanent extension of enhanced subsidies, the number of uninsured would rise by 2.2 million in 2026, growing to 3.7 million in 2027 and averaging 3.8 million per year through 2034. The Urban Institute’s more recent modeling projects that 4.8 million more people will be uninsured in 2026-a 21% increase in the uninsured population-with subsidized marketplace enrollment shrinking from 19.0 million under enhanced PTCs to 11.7 million under standard credits.
For actuaries modeling individual market risk pools, the key implication is clear: plan selection data alone is an insufficient proxy for actual enrollment in 2026. The true picture will not emerge until grace periods expire (generally by March 31 for returning enrollees) and effectuated enrollment data becomes available.
Premium Dynamics: An 18% Median Hike and the Drivers Behind It
Across 312 insurers participating in ACA marketplaces in all 50 states and D.C., the Peterson-KFF Health System Tracker analysis found a median proposed premium increase of 18% for 2026-approximately 11 percentage points higher than the prior year’s median of 7%, and the largest nationwide jump since 2018. Among those 312 insurers, 125 requested increases of at least 20%, while only four proposed decreasing premiums.
The premium increases are driven by a convergence of factors that health actuaries must decompose when analyzing rate adequacy and reserve projections:
Medical cost trend (approximately 8–12 percentage points). Rising healthcare costs-spanning hospital services, physician reimbursement, and prescription drugs-represent the foundational trend driver, consistent with what employer-sponsored plans are experiencing. GLP-1 medications are a particularly notable contributor. Kaiser Foundation Health Plan of Washington noted in its rate filing that it expects “utilization and script mix to increase by 18 percent in 2025 and seven percent in 2026,” driven “mostly by oncology and anti-diabetics, including significant growth in GLP-1 medications such as Ozempic.” Multiple insurers across state filings flagged rapidly increasing GLP-1 utilization as a premium pressure, with some Alabama insurers citing it as a primary driver of 20–29% rate increase requests.
Subsidy expiration and risk pool deterioration (approximately 4–7 percentage points). Insurers broadly assumed enhanced tax credits would expire, pricing in the anticipated departure of healthier members and corresponding increase in average morbidity. UnitedHealthcare stated directly in its Maryland filing: “Due to the expiration of the enhanced premium subsidies effective 1/1/2026, UHC anticipates a decline in enrollment due to higher post-subsidy premiums. Healthier members are expected to leave at a disproportionately higher rate than those with significant healthcare needs, increasing market morbidity in 2026.” CBO estimated that gross benchmark premiums will be 7.9% higher than they otherwise would be as the risk pool becomes sicker, on average. KFF’s overall estimate placed the average gross premium increase at approximately 26% when factoring in both medical trend and subsidy expiration effects.
Marketplace Integrity and Affordability Rule. The Trump administration finalized this rule in June 2025, tightening eligibility verification requirements, shortening enrollment periods, and strengthening income documentation standards. While most insurers estimated a small premium impact from these provisions specifically, several noted that the rule would disproportionately push healthier, lower-utilizing enrollees out of the marketplace, compounding the adverse selection effects of subsidy expiration. MVP Health Care warned in its filing that the rule’s standards “will encourage lower-cost, healthier members to be more likely to forego coverage.”
Medicaid redetermination spillover. The unwinding of pandemic-era continuous coverage requirements in Medicaid, which began in 2023, continued to affect individual market risk pools in 2025. Some enrollees transitioning from Medicaid to marketplace coverage arrived with higher acuity than expected, a trend that several carriers flagged as contributing to elevated medical loss ratios in 2025.
Adverse Selection: The Actuarial Death Spiral Risk
The theoretical risk that has long concerned health policy actuaries-the adverse selection spiral-is now being tested in real-time conditions more severe than any since the ACA’s early years. The mechanism is straightforward and well-documented in actuarial literature: when premiums rise, healthier individuals disproportionately exit, raising average claims costs among remaining enrollees, which necessitates further premium increases, which causes additional healthy member attrition, and so on.
Academy of Actuaries Warning
The American Academy of Actuaries issued a timely analysis warning that “the individual and small group ACA-market risk pools are likely to deteriorate in 2026, leading to higher rates for some plans.” Academy senior health fellow Cori Uccello noted that “changes such as the expiration of enhanced premium tax credits or increased availability of non-compliant plans could destabilize the market by increasing adverse selection and raising premiums.”
The Academy further emphasized the interconnected nature of coverage sources: “Policy changes affecting one insurance source such as ACA plans often ripple across the system, which includes other sources such as Medicaid and employer coverage-shifting enrollment patterns, altering risk pools, affecting premiums, and influencing the number of uninsured.”
Several factors mitigate outright spiral risk in 2026. The ACA’s risk adjustment program continues to operate as a permanent stabilization mechanism, transferring funds from insurers with lower-risk enrollees to those with higher-risk populations. For the 2024 benefit year, the absolute value of all risk adjustment transfers exceeded $20.8 billion across 592 participating issuers-$10.4 billion charged to lower-risk plans and $10.4 billion paid to higher-risk plans. The 2026 risk adjustment model also introduced a new pre-exposure prophylaxis (PrEP) factor in adult and child models, intended to reduce insurer incentives to restrict access to preventive medications.
Additionally, the individual mandate penalty, while reduced to $0 at the federal level, still applies in several states (California, D.C., Massachusetts, New Jersey, Rhode Island, and Vermont), providing at least some enrollment incentive for healthy individuals.
However, patterns we have observed in the rate filing data suggest actuaries are building significant risk margins into their 2026 pricing to account for unprecedented uncertainty. Some insurers submitted dual rate filings-one assuming subsidy extension, another assuming expiration-reflecting a level of pricing ambiguity that makes traditional trend analysis unreliable.
Insurer Market Dynamics: Exits, Losses, and Strategic Repositioning
The carrier landscape for 2026 reflects both exits and strategic recalibrations that will affect market competition and consumer choice in specific regions.
The most significant departure is CVS Health’s announcement in May 2025 that its Aetna subsidiary would withdraw from all ACA individual exchanges for 2026, affecting approximately 1 million enrollees across 17 states. This marks Aetna’s second exit from the exchanges in a decade-the company left in 2018 and returned in 2022. CVS CEO David Joyner cited “continued underperformance,” with the company expecting to lose up to $400 million in its ACA business during 2025. CVS set aside $448 million in Q1 2025 alone to cover excess medical claims from ACA members.
Oscar Health’s reset. Oscar Health, a technology-focused insurer concentrated in the ACA exchange market, posted a $443 million loss for 2025 after cutting its full-year guidance three times. Oscar’s medical loss ratio climbed to 86–87% in 2025, more than 5 percentage points above initial projections. However, CEO Mark Bertolini indicated the company priced aggressively for 2026 to return to profitability, projecting an MLR of 82.4–83.4% for the new plan year. Oscar estimated market contraction of 20–30% but noted early data suggested the decline would come in at the lower end of that range.
Molina Healthcare’s restructuring. Molina slashed its 2025 profit guidance three times, citing “unprecedented” medical cost trends in its ACA marketplace book, which accounts for roughly one-tenth of its members and premium revenue. In response, Molina raised ACA plan premiums by an average of 30% for 2026 and reduced its county footprint by one-fifth. CEO Joe Zubretsky left open the possibility of exiting ACA exchanges entirely if the risk pool does not stabilize.
Additional carrier exits. Beyond Aetna, several other insurers withdrew from specific state markets for 2026, including CareSource in Ohio, Chorus Community Health Plan in Wisconsin, and Mountain Health CO-OP in Wyoming. Blue Cross Blue Shield of Arizona terminated marketplace PPO offerings (while retaining HMOs), and Cigna reduced its Illinois coverage area by dropping Cook County.
These exits create actuarial implications beyond simple coverage disruption. When carriers leave, their healthiest members are more likely to exit the market entirely rather than re-enroll with a new insurer, while their sickest members are more likely to persist-further deteriorating the remaining risk pool. This dynamic compounds the already significant adverse selection pressure from subsidy expiration.
The Emerging State Patchwork: A Two-Tier Marketplace
One of the most consequential developments in 2026 is the divergence between states that have implemented supplemental subsidies and those that rely entirely on the reverted federal structure. This is creating what amounts to a two-tier ACA marketplace, with dramatically different affordability and enrollment trajectories depending on geography.
Ten states with state-based marketplaces have enacted some form of supplemental premium assistance for 2026:
| State | Key Provisions |
|---|---|
| New Mexico | Full replacement of enhanced federal subsidies for all enrollees regardless of income; enrollment grew 18% year-over-year |
| Massachusetts | $250 million additional investment ($600M total) in ConnectorCare program; protecting ~270,000 enrollees below 400% FPL |
| Connecticut | $115 million to offset subsidy loss; full replacement for households 100–200% FPL |
| Maryland | Full replacement below 200% FPL; 50% replacement for 200–400% FPL; state reinsurance program reduces unsubsidized premiums by up to 35% |
| California | $190 million for full replacement below 150% FPL; partial replacement 150–165% FPL; approximately 390,000 enrollees receiving state subsidies |
| Colorado | $70 million; full replacement 100–200% FPL; $80/month cap for individuals with partial replacement up to 500% FPL |
| Washington | Retooled Cascade Care Savings: $55/member/month for those with federal credits; $250/member/month for those who lost subsidy eligibility |
| New Jersey | Existing NJ Health Plan Savings program continues |
| New York | Existing Essential Plan and state subsidy structure continues for enrollees up to 400% FPL |
| Vermont | Existing state-funded subsidies continue; state reinsurance program in place |
The results are already visible in the enrollment data. States with robust supplemental subsidies-particularly New Mexico (up 18%), Maryland (modest growth), and D.C. (modest growth)-are experiencing enrollment increases or stability, while states relying solely on federal subsidies are seeing the steepest declines. This divergence presents unique challenges for multi-state insurers attempting to calibrate pricing and risk assumptions across jurisdictions with fundamentally different subsidy environments.
For actuaries working on individual market pricing, the implication is that state-level analysis has become even more critical. National averages for enrollment trends, risk pool composition, and premium adequacy are increasingly misleading when the underlying distribution is bimodal-with subsidized-state markets and non-subsidized-state markets following divergent trajectories.
GLP-1 Medications: The Pharmacy Cost Wild Card
Beyond subsidy dynamics, the explosive growth of GLP-1 receptor agonist medications-including semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound)-represents a structural cost pressure that health actuaries must account for in trend projections regardless of policy changes.
ACA marketplace insurers face particular cost pressures from GLP-1s because marketplace plans must cover FDA-approved medications for their indicated uses (diabetes, cardiovascular risk reduction), and utilization management tools like prior authorization and quantity limits can only partially contain spending growth. Several insurers in the Southeast reported that GLP-1 utilization was a primary driver of 20–29% rate increase requests.
The actuarial challenge is compounded by expanding indications: Wegovy is now approved for cardiovascular risk reduction and sleep apnea, Ozempic for slowing chronic kidney disease in type 2 diabetes patients, and additional approvals for heart failure and fatty liver disease may follow. Each new indication broadens the eligible population and creates additional claims exposure.
Mercer’s Survey on Health & Benefits Strategies for 2026 found that 77% of large employers consider managing overall GLP-1 costs “extremely or very important.” While employer market dynamics differ from individual market dynamics, the underlying pharmacy trend pressure flows through both channels, and actuaries pricing ACA plans cannot ignore the significant uncertainty around GLP-1 trend projections for 2027 and beyond.
Actuarial Practice Implications
For health actuaries, the 2026 ACA marketplace environment presents several concrete practice implications:
Pricing and reserving uncertainty. The combination of unprecedented enrollment volatility, subsidy-driven adverse selection, carrier exits, and regulatory changes creates an environment where traditional trend-based pricing approaches carry unusual risk. Actuaries should consider wider confidence intervals around enrollment projections and claims cost estimates, particularly for the first two quarters of 2026 before effectuated enrollment data becomes available.
Risk adjustment recalibration. The 2026 risk adjustment model updates-including the new PrEP factor and revised user fees ($0.20 PMPM, up from $0.18)-must be incorporated into financial projections. More importantly, risk adjustment transfer estimates should account for the possibility that the overall market risk pool shifts substantially as healthy members exit. In a deteriorating risk pool, a plan that was previously a net payer into risk adjustment could become a net receiver, or vice versa.
State-by-state modeling. With ten states now offering supplemental subsidies of varying generosity, and thirty states relying solely on reverted federal credits, national-level assumptions about enrollment trends, member demographics, and risk profiles are increasingly unreliable. Multi-state carriers will need jurisdiction-specific pricing models that account for state subsidy levels, reinsurance programs, and local competitive dynamics.
MLR monitoring. The ACA’s 80% minimum medical loss ratio requirement takes on new significance in a shrinking market where administrative costs are spread across a smaller membership base. Actuaries should model MLR scenarios under various enrollment decline assumptions, as some carriers may find it difficult to maintain compliance if membership drops faster than fixed administrative costs can be reduced.
Scenario planning for policy reversals. Congress continues to debate potential reinstatement of enhanced subsidies-a bill passed the House in January 2026, though Senate action remains uncertain. Actuaries should maintain scenario models for both continued standard PTCs and potential mid-year or retroactive subsidy restoration, which would create unique premium reconciliation and risk pool composition challenges.
What to Watch for the Remainder of 2026
Several key data releases and policy milestones will shape the marketplace trajectory through the remainder of the year:
- April–May 2026: Major insurer Q1 earnings calls (Centene April 28, Elevance and UnitedHealthcare typically in April, Oscar and Cigna in May) will provide early membership counts and medical cost trend commentary.
- June–August 2026: Insurers file proposed 2027 premium rates with state regulators, revealing how 2026 experience is shaping forward-looking assumptions.
- July 2026: CMS typically releases the Effectuated Enrollment Early Snapshot, reporting February 2026 enrollment measured as of March 15-the first comprehensive view of actual coverage after grace periods expire.
- Throughout 2026: Congressional activity on potential subsidy restoration, Medicaid policy changes from the One Big Beautiful Bill Act taking effect, and continued implementation of the Marketplace Integrity and Affordability rule provisions.
Conclusion
The 2026 ACA marketplace represents the most complex actuarial environment the individual market has presented since its inception. The convergence of subsidy expiration, enrollment contraction, steep premium increases, carrier exits, and an emerging two-tier state subsidy landscape creates both significant risk and, for well-positioned carriers with accurate pricing, potential opportunity as competitors withdraw.
For actuaries, the imperative is clear: granular, state-level analysis; robust scenario modeling for policy uncertainty; careful monitoring of effectuated enrollment data as it emerges; and recognition that the historical trend lines that have guided individual market pricing since 2019 are no longer reliable guides for 2026 and beyond.