Which states had the biggest gaps between ACA marketplace and employer insurance costs in 2024?

1. What the headline numbers tell us — national averages, not state gaps

KFF’s analysis summarized by Peterson‑KFF reports that in 2024 the enrollment‑weighted average premium in the individual (mostly ACA) market was $540 per member per month versus $587 for fully‑insured employer coverage — a modest national premium gap with employer plans more expensive on average ^{[1] [2]}. Those national averages are useful context but do not identify which states had the largest divergences between ACA marketplace and employer premiums ^{[1] [2]}.

2. Why a state ranking is not in these sources

The Government Accountability Office (GAO) report in our set examined comparisons of employer‑sponsored and Marketplace plans but focused on 33 Healthcare.gov states for 2022 and emphasized complications in comparing plan design and cost‑sharing rather than providing a single state‑by‑state premium gap ranking for 2024 ^[3]. In short, the available documents here do not contain a 2024 state‑level list showing the biggest gaps ^[3].

3. Technical reasons state gaps are hard to produce from these data

GAO and other analysts stress methodological challenges: enrollment weighting, differences in plan design (deductibles, networks, actuarial value), and data availability across states complicate apples‑to‑apples comparisons ^[3]. KFF/Peterson‑KFF report averages across markets but doesn’t publish a straightforward state ranking in the excerpts provided ^{[1] [2] [3]}.

4. What related analyses do provide and their limits

GAO’s work used Healthcare.gov‑platform data for 33 states in 2022 to estimate enrollment‑weighted averages, illustrating you can calculate state comparisons when consistent data exist, but that work was constrained to states using the federal platform and to an earlier year ^[3]. Peterson‑KFF’s national 2024 averages indicate convergence between markets but the provided materials do not include state breakout tables for 2024 ^{[1] [2] [3]}.

5. Other signals about why state gaps could vary

Health Affairs research and insurer filings point to structural reasons state gaps could be large in some places — for example, nongroup plans often use narrower networks and pay providers less than employer small‑group plans, which would tend to lower ACA premiums relative to employer premiums in jurisdictions with many narrow‑network issuers ^[5]. Conversely, states with higher provider prices or more generous employer contributions might show smaller or reversed gaps ^{[5] [6]}.

6. Policy and market drivers you should consider if you seek state rankings

Premium differences across states reflect provider prices, insurer competition, market participation, and policy choices (e.g., Medicaid expansion, state reinsurance, or marketplace plan rules). Peterson‑KFF and other trackers note premium changes and insurer filings for 2025–2026 driven by drug costs and utilization, but those factors vary by state and year and are not summarized here as 2024 state gaps ^{[4] [7]}.

7. Recommended next steps to get the exact state gaps for 2024

To produce a state‑by‑state ranking you would need enrollment‑weighted premium data for both the ACA individual market and employer‑sponsored (ideally fully‑insured and self‑insured separated) plans for each state in 2024. GAO’s approach (which used CMS Marketplace data and AHRQ/MEPS employer data for a subset of states) is a template ^[3]. Seek full KFF/Peterson‑KFF tables or state filings cited in their report, or GAO/CMS data releases covering 2024 if available beyond the excerpts here ^{[1] [2] [3]}.

Limitations and final note

This account uses only the documents provided. The provided KFF/Peterson‑KFF pieces give national 2024 averages but no state ranking ^{[1] [2]}. GAO and academic work show how to make state comparisons but in our set they address 2022 or methodological issues rather than listing 2024 state gaps ^{[3] [5]}. Available sources do not mention a definitive list of which states had the biggest ACA vs. employer premium gaps in 2024.