Medicaid Membership Stabilizes After Three-Quarter Decline
The next few weeks are an exciting time for those who monitor insurance market share shifts. This year’s open enrollment season for the public health insurance exchanges (HIE) set another record-breaking high, for the fourth year in a row. According to Kaiser Family Foundation, 24.3 million people signed up for ACA plans in 2025, more than double the number four years ago.
As we wait for the 2025 insurer data to emerge, it’s important to remember why monitoring large-scale enrollment shifts is useful in the first place. For manufacturers, understanding the payer mix for a particular product’s patient population is essential for determining potential access barriers. Providers must also keep an eye on enrollment shifts, making policy changes as necessary to ensure access and maintain care continuity. And for healthcare IT vendors, assessing market fluctuations at the insurer level informs the identification of potential growth areas for their clients.
AIS Health and MMIT researchers are conducting our annual payer survey, auditing public filings for the first quarter of 2025. We expect to publish a look at market trends in MMIT’s Directory of Health Plans at the end of June. In the meantime, let’s take a look at the Q4 2024 enrollment numbers—plus a sneak peek at Q1 2025 data for Medicare Advantage membership.
Medicaid Membership Normalizes in Q4 2024
After states resumed eligibility redeterminations in April 2023, following a multi-year pause, Medicaid enrollment dropped rapidly and continued to fall. In the first half of 2024, Medicaid HMO plans lost almost 1.4 million members, while Medicaid fee-for-service (FFS) enrollment decreased by more than 1.7 million members. The decline slowed in Q3, as states began winding down their Medicaid disenrollment: Medicaid HMO membership fell by 527K, while Medicaid FFS membership dropped by only106K.
With the Q4 2024 enrollment data, it’s clear that states have finally completed their Medicaid disenrollments from redeterminations. Decreases in the Medicaid space are flattening. Medicaid HMO membership fell by 204K since December 2024, a significant slowdown after drops of 1.1M in Q2 and 527K in Q3. Similarly, Medicaid FFS membership losses have slowed this quarter, with a decline of only 135K members.
Notable insurer-level changes in the managed Medicaid space include Humana, which added more than 107K beneficiaries since last quarter. Aetna lost the most Medicaid members (98K), largely due to a contract exit in Kansas that dropped 128K members. Elevance Health’s Medicaid enrollment declined by 85K, largely due to a contract loss in Kentucky that was somewhat offset by a contract gain in Kansas.
Modest Gains in HIE Enrollment
At the beginning of 2024, Medicaid disenrollment was in full swing, and the public health insurance exchange (HIE) segment saw a huge jump in enrollment, increasing by nearly 3.4 million members. In Q2, this segment experienced minor attrition, losing almost 148K members, in part due to new beneficiaries failing to pay their first monthly premium. By Q3, the segment had rebounded, gaining an additional 290K members.
Although the Q4 data shows a modest gain of about 88K members for the HIE market, we can expect a significant enrollment jump after the Q1 2025 numbers are reported. In Q4, Centene Corporation saw minor losses of 121K members, which represents less than 3% of its exchange members. EmblemHealth lost roughly 52K members, due to Molina’s acquisition of its ConnectiCare subsidiary. Molina captured the largest shift in the public exchange space, adding 110K lives since Q3, mostly due to gains in Essential Plan membership in New York.
The recent explosion in year-over-year growth for the HIE market has been driven by the IRA’s extension of the 2021 American Rescue Plan (ARP), which provides premium subsidies to eligible members whose income is more than 400% of the federal poverty level. While these premium subsidies are currently in effect through the end of 2025, their future remains uncertain. Unless Congress votes to extend these credits, millions of HIE members will likely become uninsured in 2026.
Increased Medicare Advantage, Dual-Eligibility Enrollment
After a strong start to 2024, with gains of over 1M, Medicare Advantage (MA) and dual-eligibility plans went on to gain 260K members in Q2 and 220K members in Q3 2024.
After a turbulent fall 2024 open enrollment season marked by myriad market exits, MA and duals plans gained nearly 600K members this year. Given the movement of beneficiaries aging into Medicare, this is an expected increase, but the numbers lag behind 2024’s gains.
Notable payer changes include shifts in Humana’s membership. After exiting 13 counties, Humana lost nearly 294K Medicare members in 2025. Aetna also saw significant decreases, losing approximately 161K members. On the net positive side, both UnitedHealthcare and Elevance Health increased their membership by 286K and 203K, respectively, possibly by scooping up members from other large national insurers.
In Q4 2024, Medicare FFS membership also increased by 135K beneficiaries. As Medicare FFS data lags behind MA data, this total is as of December 2024, and does not contain data from 2025. Health Care Service Corporation’s acquisition of Cigna’s Medicare business, which closed in March, is also not reflected in this update, as the companies are finalizing the details of the deal.
Commercial Group Enrollment Continues to Fall
At the end of Q1 2024, enrollment in commercial group plans had dropped significantly, with decreases of 953K for group risk plans and more than 1.3 million for self-funded and administrative services only (ASO) plans. The second quarter saw a slight decrease of 85K for group risk plans, while ASO/self-funded plans lost 1.3 million members. In Q3, group risk plans continued to decline, with a loss of 121K members, while ASO/self-funded plans managed to gain 96K members.
In the last quarter of the year, commercial group enrollment again declined. Group risk plans dropped 510K members, largely fueled by losses in the small group market (575K). Meanwhile, ASO/self-funded plans made modest gains of nearly 118K members, in large part due to Cigna Corporation picking up an additional 76K ASO members.
Notable changes in the commercial group space include UnitedHealthcare, which lost 55K commercial risk members overall. However, decreases in the group side of its business were balanced by gains in individual enrollment. Humana finally completed its departure from the commercial risk segment, with only 300 commercial risk members and 3,800 non-Tricare ASO members remaining.
To track enrollment trends and payer affiliations, subscribe to MMIT’s Directory of Health Plans.
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