ACA Marketplace in 2024: low-income enrollment up, silver plan selection down

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CMS has published its 2024 Marketplace Open Enrollment Period Public Use Files, providing detailed breakouts of enrollment by income, metal level selection, demographics, etc.

We already knew that enrollment increased by 31% nationally this year, spurred in part by the Medicaid unwinding — that is, the resumption of Medicaid redeterminations and disenrollments after a three-year pandemic-induced moratorium. While there’s always much to explore in the PUFs, two facts jump off the page for me:

• Enrollment growth was heavily concentrated at low incomes — up 61% at 100-138% FPL and 54% in the slightly broader 100-150% FPL bracket. That’s perhaps not surprising, given that CMS announced that 2.4 million Medicaid disenrollees had enrolled in the 32 states using the federal platform, HealthCare.gov (and perhaps 2.9 million nationally, by Charles Gaba’s estimate). Year-round enrollment at incomes up to 150% FPL has likely also boosted enrollment in this bracket [added 3/23/24].

• The decline in silver plan selection at low incomes that I flagged last March has continued. That is, growing numbers of low-income enrollees are forgoing Cost Sharing Reduction, available only with silver plans. At incomes up to 200% FPL, CSR makes silver plans roughly equivalent to platinum. Since March 2021, at least two CSR-enhanced silver plans in each rating area, with an actuarial value of 94%, are available at zero premium to enrollees with income up to 150% FPL. In the 150-200% FPL bracket, the benchmark (second cheapest) silver plan costs 0-2% of income (topping out at about $45/month for a single person) and has an actuarial value of 87%. Yet silver plan selection in the 100-150% FPL bracket was just 76.4% in HealthCare.gov states, down from 84.9% in 2022 and 89.3% in 2017. In the 150-200% FPL bracket, silver crashed from 69.5% last year to 56.7% this year. It was 83.2% in 2017.

Let’s look first at enrollment growth by income.

Too many low-income ACA marketplace enrollees are forgoing high-CSR silver

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Today is the ACA’s 13th birthday, and CMS released its final enrollment report and detailed enrollment data for the 2023 Open Enrollment Period (OEP) in a celebratory vein. The good news: Enrollment nationally overall is up 13% year-over year and 36% since 2021, after two years with premiums subsidies substantially boosted by the American Rescue Plan Act of March 2021. (As I noted here when OEP was mostly completed, enrollment growth is heavily concentrated in the twelve states that had not enacted the ACA Medicaid expansion as of OEP 2023.) New enrollment increased by 21%.

In OEP 2022 — the first OEP in which there was no income cap on subsidy eligibility — enrollment growth was highest at high incomes. In marked contrast, this year it’s concentrated at low incomes. In the 33 states that use HealthCare.gov (which include all of the twelve states that haven’t expanded Medicaid), enrollment at incomes between 100% and 150% of the Federal Poverty Level (FPL) increased from 32% of all enrollment in 2022 to 37% this year, rising 20.4%, from 4,640,092 in OEP 2022 to 5,588,315 million in 2023.

In ACA marketplace in 2022, too much underinsurance (bronze plan selection) at low incomes

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We have had plenty of time to celebrate the 21% surge in ACA marketplace enrollment, most likely triggered primarily by the major boosts to premium subsidies provided last March by the American Rescue Plan Act (ARPA). Now, with CMS's Public Use Files tracking marketplace enrollment for 2022 released on the ACA's 12th anniversary, it's time for some disappointment.  

In the 33 HealthCare.gov states, for which CMS provides detailed plan selection breakouts, the ARPA subsidy boosts did not reduce underinsurance as much as might have been expected during the Open Enrollment Period (OEP) for 2022.  That is, silver plan selection at low incomes (up to 200% FPL), where Cost Sharing Reduction (CSR) makes silver plans far and away the best value for almost all enrollees, modestly reversed a four-year slide, but not nearly as much as might have been expected. 

In HealthCare.gov states this year, 60% of enrollees had incomes below 200% FPL, and 80% of them selected silver plans. 

Enrollment by metal level at low incomes

HealthCare.gov states

100-150% FPL

Year	% bronze	% silver
2017	9.2%	89.3%
2018	9.9%	87.7%
2019	10.4%	88.3%
2020	12.1%	86.8%
2021	16.2%	82.7%
SEP 2021(0-150%)		93.0% (estimate)
2022	14.1%	84.9%