Open Enrollment Audiences for Health Insurance Marketers
Every adult in the United States is scored for fit to five ways of buying health coverage: ACA Marketplace, Employer-Sponsored, COBRA, Medicare Advantage and Medigap. Each person counts toward the one channel they fit best, so the five audiences never overlap. At $1.50 to $3.00 CPM, these audiences are priced at approximately 50% or less of the market rate, with results reported every week.
The 2027 calendar is tighter. Medicare Annual Enrollment runs October 15 to December 7, 2026. ACA Open Enrollment runs November 1 to December 15, 2026 in HealthCare.gov states, about six weeks instead of the eleven buyers are used to, and no state exchange may run past December 31.
ACA Marketplace
Nov 1 to Dec 15, 2026 54Mqualified Under 65 · ages 26-64Employer-Sponsored
Employer-set, mostly fall 92Mqualified Under 65 · ages 26-49COBRA
60 days, year-round 37Mqualified 65 and over · ages 65+Medicare Advantage
Oct 15 to Dec 7, 2026 57Mqualified 65 and over · ages 65+Medigap
6 months from age 65 4.8MqualifiedThe five channels compared qualified tier, score 75+
| Channel | Who | Window | Qualified reach | High-Fit lift | Avg index |
|---|---|---|---|---|---|
| ACA Marketplace | Nov 1 to Dec 15, 2026 | 53,699,767 | 3.64× | 72.0 | |
| Employer-Sponsored | Employer-set, mostly fall | 91,602,315 | 1.39× | 89.4 | |
| COBRA | 60 days, year-round | 36,797,625 | 1.83× | 72.4 | |
| Medicare Advantage | Oct 15 to Dec 7, 2026 | 57,130,909 | 3.44× | 122.3 | |
| Medigap | 6 months from age 65 | 4,809,201 | 2.40× | 168.3 |
Reach figures are direct counts from Semcasting's national scoring of 251,722,617 people, restricted to each person's single best-fitting channel.
The Digital Activity Layer
A national engagement overlay. Every U.S. individual is linked to a Digital Activity Score that sorts them into six engagement tiers, so any channel audience can be split by how reachable it is digitally.
How it works
The score is a national reference, not a channel-qualified segment. It is deliberately kept out of the channel fit scores: fit is essentially flat across digital-activity tiers, which confirms engagement is an independent dimension rather than a restatement of age, income or geography. That makes it useful as a second layer on top of any channel audience.
National distribution
| Tier | Share | People | Households |
|---|---|---|---|
| Most Active | 26.7% | 67,212,506 | 37,229,854 |
| Above Average | 26.6% | 66,960,774 | 37,090,416 |
| Average | 18.4% | 46,318,731 | 25,656,528 |
| Below Average | 13.8% | 34,739,048 | 19,242,396 |
| Least Active | 14.4% | 36,249,442 | 20,079,022 |
| No Activity | 0.2% | 503,464 | 278,875 |
Percentages sum to 100.1% due to rounding in the source snapshot.
Method, sources and limits
Three ideas explain almost every figure on these pages: a fit score, three tiers, and an index against the U.S. population.
How the scoring works
Each person in the 251,722,617-record national scoring is scored 0 to 100 for every channel using an additive rubric. A high score does not mean someone has that coverage. It means their profile looks like the people who do.
| Component | Points | What it measures |
|---|---|---|
| Base | 40 | Every person starts here |
| Age fit | 0 to 25 | Distance from the channel's target age band |
| Affluence fit | 0 to 20 | Distance from the channel's target income band |
| State coverage context | 0 to 15 | State uninsured rate, coverage-type share, Medicaid expansion status |
| ZIP Marketplace bonus | 0 to 10 | ACA Marketplace only: CMS Marketplace consumer counts by ZIP |
Three tiers
| Tier | Score | When to use it |
|---|---|---|
| High-Fit | 85+ | Tightest, highest-confidence segment. Conversion and direct response. |
| Qualified | 75+ | The core audience and the default buy. Most campaigns. |
| Extended Reach | 65+ | Widest reasonable net. Awareness and upper funnel. |
The index
On the profile charts, 100 means a group appears in the qualified audience at exactly the rate it appears in the overall population. 150 means half again as often. 50 means half as often. The average index score on each channel page summarizes how sharply defined that audience is.
Data sources
- FederalU.S. Census Bureau, American Community Survey Briefs, Health Insurance Coverage by State: 2023 and 2024 (ACSBR-024)
- Population surveySHADAC State Health Compare, Health Insurance Coverage Type by Total, 2024
- FederalCMS 2026 Open Enrollment Period ZIP-level Public Use File
- FederalCMS 2025 Marketplace Open Enrollment Period Public Use Files and Health Insurance Exchanges 2025 Open Enrollment Report
- FederalCMS Medicare enrollment reporting
- Industry reportingHealthcare Finance News, citing CMS: Overall ACA Reach national estimate
What these numbers are
Marketing propensity and audience-sizing estimates built for media planning. They are not insurance eligibility, subsidy qualification, or coverage determinations for any individual.
How reach is counted
Reach figures are direct counts from the full national scoring, restricted to each person's single best-matching channel, so the five channels' reach figures never overlap. They are not extrapolated from a sample.
Limits
Age and income fields contain "unknown" shares that receive a below-average default score. State and county rankings reflect national geography but have not been independently benchmarked against Census population counts. Treat the figures as a strong directional planning input, not a certified audience-size guarantee.