ACA Benchmark Premiums Jump 21.7% in Largest Surge Since 2018: Rate Filing Decomposition

From reviewing insurer rate filings across 312 carriers and tracking the assumptions embedded in each, the most striking pattern is how differently carriers are pricing the same subsidy expiration uncertainty. One insurer applied a 1.044 morbidity adjustment factor for anticipated risk pool deterioration. Another in the same state applied 1.0025. Both filed in the same regulatory environment, drawing from the same CMS enrollment data, yet arrived at morbidity assumptions that differ by a factor of nearly 18. That spread tells you more about the state of health actuarial pricing in 2026 than any single premium number.

The Peterson-KFF Health System Tracker analysis of 312 insurers across all 50 states and the District of Columbia found a median proposed premium increase of 18%, with the 25th-to-75th percentile range spanning 12% to 27%. Only four of 312 insurers proposed rate decreases. One hundred and twenty-five filed for increases of 20% or more. The average gross premium increase across all ACA marketplace plans reached approximately 26%, according to KFF's separate analysis, while the benchmark (second-lowest-cost silver plan) increase averaged 21.7% when weighted across state-based marketplaces and Healthcare.gov states.

This is not a normal rate cycle. The 2020-to-2025 period saw annual ACA premium growth averaging roughly 2.0%, a stretch of stability that lulled observers into treating the individual market as a solved problem. The 2026 filing season shattered that assumption. What follows is a decomposition of the rate increase into its component actuarial drivers, drawn from the filings themselves.

Decomposing the 21.7% Benchmark Increase

Rate filings are built from layered assumptions. Each insurer starts with a base experience period, projects medical trend forward, then applies adjustments for anticipated changes in enrollment composition, regulatory environment, and external cost pressures. The 2026 filings decompose into four primary components, each contributing a distinct portion of the total increase.

Rate Driver	Estimated Contribution	Key Assumption
Medical cost trend (unit cost + utilization)	~8 percentage points	7-8% underlying trend; hospital labor costs, procedure volumes
Enhanced subsidy expiration (morbidity shift)	~4 percentage points	Healthier enrollees exit; 2.9-6.5% morbidity increase
GLP-1 and specialty pharmacy	~3-5 percentage points	25-30% quarterly utilization growth; 2% of members, 50%+ of drug spend
Tariff-related medical cost uncertainty	~3 percentage points	Import costs for drugs, devices, supplies
Residual (risk adjustment, admin, margin)	~2-4 percentage points	Administrative cost inflation, profit and risk loads

These components do not add linearly because they compound through the rating formula, but they capture the primary forces at work. Each deserves closer examination.

Medical Cost Trend: The 8% Baseline That Preceded Everything Else

Before any subsidy or enrollment adjustment, insurers started their 2026 projections from an underlying medical cost trend of approximately 7% to 8%. This figure encompasses both unit cost increases (what providers charge per service) and utilization changes (how many services enrollees consume). The Peterson-KFF analysis found that insurers specifically cited increasing labor costs in hospital settings, ongoing post-pandemic utilization recovery, and general inflationary pressures as components of this baseline.

This trend rate alone would have produced a significant filing. For context, the Segal Group's 2026 health plan cost trend survey projected 8.5% for large group plans. PwC's Health Research Institute estimated medical cost trend at 8.0% for 2026. The SOA Getzen model, which health actuaries use for long-term trend projection, has been signaling persistent above-average growth for several quarters. These figures align with what individual market insurers are embedding in their filings.

The key actuarial question is whether this 7-8% baseline is a temporary post-pandemic reversion or a structural shift. Hospital labor costs, which account for roughly 30-40% of medical trend, show no sign of moderating. Nurse vacancy rates remain elevated, and health systems continue to rely on costly traveling and contract staff. Procedure volumes for deferred surgeries have largely normalized, but new utilization from GLP-1-adjacent monitoring and specialist visits is additive.

GLP-1 Drug Costs: 2% of Members Driving 50% of Drug Spend

The GLP-1 drug class has become the single largest pharmacy cost disruptor in 2026 rate filings. Drugs like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) are prescribed for diabetes and, increasingly, weight management. Their cost and utilization trajectory has forced health actuaries to fundamentally rethink pharmacy trend assumptions.

MVP Health Plan of Vermont disclosed in its rate filing that GLP-1 costs rose 25-30% per quarter during 2024, with Q4 2024 costs nearly doubling the full-year 2023 total. Kaiser Foundation Health Plan of Washington projected an 18% utilization increase for 2025 and a further 7% increase for 2026. These are not marginal adjustments; they represent a shift in the pharmacy cost distribution that actuaries have not seen since the hepatitis C direct-acting antiviral wave of 2014-2016.

The challenge for pricing actuaries is the dual nature of GLP-1 cost exposure. Members using these drugs for FDA-approved diabetes indications generate claims that are relatively predictable and supported by clinical evidence of long-term cost offsets (cardiovascular risk reduction, fewer hospitalizations). Members using them for weight management represent a population whose long-term cost trajectory is deeply uncertain. Studies of GLP-1 discontinuation show that patients regain weight after stopping treatment, and cardiovascular risk factor improvements regress toward baseline, suggesting indefinite utilization for the weight management cohort.

Blue Cross Blue Shield of Massachusetts took one of the most visible actions in 2026 filings: discontinuing weight-loss coverage for GLP-1 drugs entirely, which the insurer estimated would reduce premiums by approximately 3%. This decision illustrates the pricing bind. Covering GLP-1s for weight management exposes the plan to rapidly growing utilization at net prices of $617 to $766 per 30-day supply. Excluding them risks adverse selection as enrollees who need these medications migrate to plans that cover them.

The Employee Benefit Research Institute (EBRI) modeled the employer-market analog and found that GLP-1 coverage drives premium increases of 5.3% to 13.8%, depending on adherence rates, cost-sharing design, and eligibility restrictions. In the individual market, where plans have less flexibility to impose prior authorization barriers compared to large self-funded employers, the exposure is arguably greater. Harvard researchers estimated that roughly 30% of health insurance premium increases in 2026 are attributable to GLP-1 utilization across all market segments.

The Subsidy Cliff: How 4 Percentage Points of Morbidity Shift Enter the Rate Filing

The enhanced premium tax credits (PTCs) enacted under the American Rescue Plan Act of 2021 and extended through the Inflation Reduction Act expired on December 31, 2025. This expiration removed the income cap on subsidy eligibility (previously, households above 400% of the federal poverty level received no subsidies) and reverted the subsidy formula to its pre-2021 structure, where enrollees above 400% FPL face the full unsubsidized premium.

KFF estimated that this change would more than double average premium payments for subsidized enrollees, from an average of $888 per year in 2025 to $1,904 in 2026, a 114% increase in out-of-pocket costs. The Urban Institute projected that 4.8 million people would lose coverage if enhanced PTCs expired, with total subsidized marketplace enrollment declining by 7.3 million (38%) compared to a scenario where the credits were extended.

For pricing actuaries, the subsidy expiration creates a classic adverse selection spiral in miniature. Healthier enrollees, who tend to be younger and have lower utilization, are the most price-sensitive. When their net premiums double, they are the first to leave. The remaining risk pool is older, sicker, and more expensive to cover. Insurers must price for this deteriorated pool, which raises premiums further, which drives out the next tranche of relatively healthy enrollees.

The rate filing data reveals how insurers quantified this dynamic. The Peterson-KFF analysis found that the majority of 312 insurers factored subsidy expiration into their 2026 filings, with an average impact of approximately 4 percentage points on the total premium increase. But the range of carrier-specific morbidity adjustments is striking:

Carrier	State	Morbidity Adjustment Factor	Rationale
UnitedHealthcare (Optimum Choice)	Maryland	1.044	Healthier members exit at disproportionately higher rate
Wellpoint Washington	Washington	1.016	Anticipated statewide average morbidity change
MVP Health Plan	New York	1.0025	Market-wide index rate adjustment

UnitedHealthcare's filing for Optimum Choice in Maryland explicitly states: "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, with healthier members expected to leave at a disproportionately higher rate than those with significant healthcare needs, increasing market morbidity in 2026." That language captures the actuarial mechanism precisely. The 1.044 factor implies an expected 4.4% increase in average per-member morbidity, driven entirely by composition change rather than any change in underlying health status.

Compare that to MVP's 1.0025 in New York. Both carriers are licensed health insurers pricing the same federal subsidy expiration. The difference reflects divergent assumptions about state-level enrollment elasticity, the composition of their current book, and the degree to which state premium alignment programs (discussed below) will cushion the blow.

Enrollment Composition Shift: Metal Level Selection Tells the Risk Pool Story

The CMS 2026 Open Enrollment Period final report confirmed 23.1 million plan selections, down 1.2 million (approximately 5%) from the 2025 OEP. That topline decline is significant but manageable. The metal level composition shift is far more telling.

Metal Level	2025 Share	2026 Share	Change
Bronze	~30%	~40%	+10 percentage points
Silver	~56%	~42%	-14 percentage points
Gold	~13%	~17%	+4 percentage points
Platinum/Catastrophic	~1%	~1%	Minimal change

Bronze plan enrollment jumped by 26% year over year, while Silver plan enrollment dropped 28%. This is not random consumer preference. It is a direct consequence of subsidy mechanics. Under the enhanced PTCs, the benchmark Silver plan was essentially free or near-free for many low-income enrollees. Silver plans also carry cost-sharing reductions (CSRs) for households below 250% FPL, making them the most valuable coverage tier for the subsidy-eligible population. When enhanced subsidies expired, the net premium for Silver plans increased dramatically, pushing price-sensitive enrollees into Bronze plans with lower premiums but higher deductibles.

The Gold plan increase of 4 percentage points (from 13.2% to 17.2% of selections, a gain of nearly 770,000 enrollees) is counterintuitive in a rising-premium environment. It signals that a subset of enrollees, likely higher-income individuals who previously benefited from the extended subsidy eligibility above 400% FPL, opted for richer coverage rather than dropping out entirely. This cohort is likely older and higher-utilizing, which further concentrates morbidity in the remaining risk pool.

For actuaries tracking the ACA risk adjustment program, these composition shifts create significant transfer payment uncertainty. Bronze-to-Silver migration changes the denominator in the statewide average premium calculation. Carriers with disproportionately high Silver enrollment in 2025 may find their risk adjustment transfer positions shifting materially as enrollees redistribute across metal levels.

The January Premium Payment Signal: 14% Non-Payment and What It Implies

Wakely Consulting Group published one of the most consequential post-enrollment analyses of the 2026 cycle. Their data showed that, on average, only 86% of enrollees paid their first premium in January 2026. Approximately 14% of enrollees nationwide failed to make their initial payment, with some states reaching non-payment rates of 25% or more.

The morbidity differential between payers and non-payers is the critical actuarial finding. Wakely reported that enrollees who made premium payments in January had, on aggregate, 10% higher morbidity than those who did not pay. This confirms the adverse selection hypothesis embedded in the rate filings: the healthier members are the ones leaving.

Wakely projects total effectuated ACA enrollment to drop by 3.8 million to 5.8 million during 2026 when accounting for non-payment, mid-year attrition, and SEP churn. A 17% decline would produce average effectuated enrollment of approximately 18.5 million; a 26% decline would reduce it to roughly 16.5 million. Either scenario represents the largest single-year enrollment contraction in ACA marketplace history.

From a pricing perspective, the gap between OEP selections (23.1 million) and projected effectuated enrollment (16.5-18.5 million) creates a material earned premium shortfall relative to filed rates. Insurers who priced for a morbidity adjustment in the 1.02-1.04 range may find that the actual adjustment needed is larger if attrition skews even more heavily toward healthy members through mid-year.

Tariff Uncertainty: The 3-Percentage-Point Wild Card

A newer variable in 2026 rate filings is the impact of import tariffs on medical costs. KFF reported that several individual market carriers included upward adjustments of approximately 3 percentage points specifically to account for anticipated increases in drug and medical device costs tied to tariff policy.

The exposure is substantial. An estimated 62% of medical devices used in the United States are imported, and nearly 70% of U.S.-marketed devices are manufactured solely outside the country, according to industry data compiled by MedDeviceGuide. For pharmaceuticals, an Ernst & Young analysis estimated that a 25% tariff on pharmaceutical imports could increase national drug costs by approximately $51 billion annually.

In the small group market, KFF found that one-quarter of 88 rate filings explicitly mentioned tariffs, noting that new import tariffs are expected to increase the cost of certain brand-name and specialty drugs, especially those without generic alternatives. The individual market filings show a similar pattern, though the magnitude of the adjustment varies by carrier depending on their pharmacy benefit structure and the extent to which they negotiate directly with manufacturers versus relying on pharmacy benefit managers.

For health actuaries, tariff-related trend adjustments represent a new category of assumption that sits outside traditional medical cost projection frameworks. Unlike medical trend, which can be calibrated against historical utilization and unit cost data, tariff impacts depend on trade policy decisions that can change rapidly. Carriers that loaded 3 percentage points into their 2026 filings may find themselves over- or under-reserved depending on how tariff negotiations unfold through the policy year.

Premium Alignment: State-Level Responses to Cushion the Blow

Approximately a dozen states implemented Premium Alignment pricing policies for 2026, with three states (Arkansas, Illinois, and Washington) newly adopting the approach specifically in response to the enhanced tax credit expiration. Premium Alignment, sometimes called "Silver loading" or "Silver switching," allows insurers to concentrate the cost-sharing reduction subsidy load onto on-exchange Silver plans, effectively raising Silver premiums to generate larger premium tax credits while keeping Bronze and Gold plans competitively priced.

The effectiveness of these programs varies significantly. Washington State's benchmark premium increase was moderated to 21.2% on average, with only 2.3% attributable specifically to subsidy expiration, according to ACA Signups tracking data. Arkansas saw a 26.2% average increase, with approximately 7 percentage points linked to subsidy expiration. The difference reflects state-specific market dynamics, the number of competing carriers, and how aggressively the state exchange implemented the alignment policy.

For pricing actuaries working in states with Premium Alignment, the interaction between silver loading, CSR funding, and the revised PTC formula creates a multi-layered calculation. The base rate must account for the loaded Silver premium, the unloaded off-exchange rate, the expected subsidy amount at various income levels, and the resulting enrollment distribution across metal levels. This complexity introduces additional model risk that is difficult to validate against historical data because Premium Alignment at this scale has limited precedent.

Carrier Divergence: The Spread That Defines 2026 Filing Season

The range of proposed rate changes across 312 insurers spans from -10% to +59%. That 69-point spread captures genuine differences in actuarial judgment about the same underlying uncertainties. Several factors drive this carrier-level divergence.

First, geographic concentration matters. A carrier with heavy enrollment in a single state faces different adverse selection dynamics than a national carrier that can pool risk across markets. State-level regulatory environments also differ: states with active reinsurance programs, such as Minnesota, Alaska, and Oregon, dampen premium volatility relative to states that rely solely on the federal framework.

Second, book composition entering 2026 determines exposure to the subsidy cliff. Carriers whose 2025 enrollment skewed heavily toward subsidy-eligible members below 200% FPL face a different attrition profile than carriers whose books contain a larger share of members between 200% and 400% FPL. The latter group sees the largest absolute premium increase from subsidy reversion and is most likely to exit.

Third, GLP-1 coverage decisions create a bifurcation in pharmacy trend assumptions. Carriers that cover GLP-1s for weight management must price for rapidly growing utilization with uncertain persistence rates. Carriers that exclude weight management coverage (like BCBS Massachusetts) can reduce their pharmacy trend by approximately 3%, but they risk losing enrollees who want that coverage and may also face regulatory pressure in states considering GLP-1 coverage mandates.

Fourth, the tariff adjustment is discretionary. While some carriers loaded 3 or more percentage points for tariff impacts, others chose not to include any tariff adjustment, betting that the policy environment would stabilize before costs materialize in the 2026 policy year. This binary choice alone explains a meaningful portion of the cross-carrier filing spread.

Why This Matters for Health Actuaries

The 2026 ACA rate filing season is a case study in pricing under compounding uncertainty. Several implications stand out for practicing health actuaries.

Risk adjustment transfer volatility. The metal level composition shift, combined with enrollment attrition concentrated among healthier members, will produce risk adjustment transfer payments that differ significantly from historical patterns. Carriers should model transfer positions under multiple enrollment scenarios rather than relying on point estimates from prior years. The gap between OEP selections and effectuated enrollment makes the denominator in statewide average premium calculations unstable.

Reserve adequacy under enrollment contraction. If effectuated enrollment drops 17-26% as Wakely projects, carriers will earn fewer premium dollars than their filed rates anticipated. Per-member costs, however, may exceed filed projections if the morbidity shift is larger than the adjustment factor applied. Actuaries should stress-test their 2026 reserves against a scenario where both enrollment and per-member cost assumptions miss simultaneously.

GLP-1 trend credibility. The GLP-1 drug class is growing fast enough that historical trend extrapolation is unreliable. Quarterly utilization growth of 25-30%, as MVP Vermont reported, means that any trend assumption based on calendar year 2024 experience is already stale by the time 2026 claims emerge. Pricing actuaries should consider building separate GLP-1 cost models that project utilization, persistence, and unit cost independently rather than embedding them in an aggregate pharmacy trend.

Tariff assumption documentation. Tariff-related trend adjustments are new to most health actuarial pricing models. Given the uncertainty in trade policy, actuaries filing rates that include tariff loads should document the assumption explicitly, specify the conditions under which it would be revised, and consider whether mid-year rate adjustment mechanisms (where state law permits) would be appropriate if tariff policy changes materially.

ASOP applicability. ASOP No. 25 (Credibility Procedures) and ASOP No. 56 (Modeling) both bear on the assumptions underlying 2026 filings. The subsidy cliff scenario has no direct historical analogue: the enhanced PTCs have been in effect since 2021, and the pre-2021 individual market operated in a fundamentally different enrollment and subsidy environment. Actuaries relying on pre-2021 experience to calibrate morbidity adjustments should document why that experience is relevant to a market that is structurally different from the one that generated it.

The 2027 feedback loop. Whatever happens in 2026 enrollment and claims will feed directly into 2027 rate filings. If morbidity shifts exceed filed assumptions, insurers will need to file larger increases for 2027, which will drive further attrition, which will further concentrate the risk pool. Conversely, if Congress extends enhanced PTCs (as several bills have proposed), the morbidity assumptions in 2026 filings will prove too conservative, creating either excess reserves or an opportunity for competitive rate reductions in 2027. Health actuaries should prepare both scenarios for their rate development frameworks now, rather than waiting for legislative clarity that may not arrive until late 2026.