Why It Matters

Health insurance exchange enrollment data sources differ in timing, coverage and definition. A new Congressional Research Services report says exchanges, also called marketplaces, have been established in every state under the Patient Protection and Affordable Care Act, as amended. That nationwide framework includes individual exchanges, where consumers can shop for private health insurance coverage, and Small Business Health Options Program (SHOP) exchanges, where small businesses can shop for that coverage.

The Big Picture

Pre-effectuated enrollment counts people who selected a plan but may not have paid the first premium, and those figures are often released during or soon after open enrollment.

Effectuated enrollment data — which count individuals who selected a plan and submitted the first premium payment — are available through Data.CMS.gov, while some older datasets are archived on the CMS Archive page. The 2026 Marketplace Open Enrollment Period public-use files contain final national, state, and county data for the full open enrollment period, including health insurance applications, Qualified Health Plan selections, and stand-alone dental plan selections.

The 2026 monthly effectuated-enrollment dataset provides national and state counts, while annual effectuated enrollment data are available at those levels since 2016 and include APTC and CSR enrollment and the average premium with APTC.

The Bottom Line

The February effectuated-enrollment tables cover people with active policies at any point in February from 2017 through 2025, giving the series a defined monthly population and period.

The report’s most recent congressional-district data are from 2024, include advance premium tax credit information, are limited to HealthCare.gov states, and reflect the boundaries of the 118th Congress. County-level marketplace data vary by year and generally include total plan selections, financial assistance, and demographic information, although certain data elements are available only for counties in HealthCare.gov states.

The resource covering 2019–2024 small-group enrollees without claims includes nationwide data and data for all states, while a recent CMS resource contains certain small-group enrollment data for markets both on and off SHOP exchanges, and small-group figures generally combine on-exchange and off-exchange enrollment.

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