Why Subsidizing Higher-Income Insurance Is Less Efficient

A new NBER working paper by Anuj Gangopadhyaya and Robert Kaestner directly measures the efficiency of two competing health insurance subsidy approaches. The authors find that enhanced premium subsidies for higher-income groups generate a lower coverage rate per dollar spent compared with expanding public insurance to low-income populations, especially in non-expansion states. The finding lands during a live policy window. The enhanced premium subsidies enacted through the American Rescue Plan and extended through 2025 are set to expire unless renewed. Roughly a dozen states have not expanded Medicaid under the Affordable Care Act. If the paper's efficiency calculus gains traction among lawmakers, the policy trade-off could shift toward Medicaid expansion rather than subsidy renewal.

Policy Mechanism and Market Read-Through

The naive reading of this paper is that it simply confirms what health policy analysts already know: targeting the poorest populations yields higher coverage per dollar. The better market read requires understanding the subsidy design and its effect on insurer risk pools. Enhanced premium subsidies reduce the out-of-pocket cost of exchange plans for individuals earning between 150% and 400% of the federal poverty level. This keeps healthier, higher-income people in the risk pool. Diverting those dollars to Medicaid expansion would cover a sicker, lower-income population. The Centers for Medicare & Medicaid Services data shows that exchange enrollees have a lower claims cost per member than Medicaid enrollees. Redirecting subsidies could improve coverage rates but degrade commercial risk pool quality. For managed care organizations, the read-through is nuanced. Companies with heavy exposure to Medicaid managed care such as Centene and Molina Healthcare could benefit from a renewed push for expansion. Insurers with a strong individual market footprint under the ACA exchanges could face headwinds if subsidies are allowed to lapse or are redirected.

The Decision Point for Health Insurers

The next concrete catalyst is the 2025 budget reconciliation window. Enhanced premium subsidies must be renewed or allowed to expire by the end of 2025. The Congressional Budget Office will score any extension or reform. If the CBO incorporates an efficiency metric similar to the one in this paper, the budget savings from letting subsidies expire could be redirected to incentivize non-expansion states. That is the risk scenario for exchange-heavy insurers: they lose subsidy-dependent enrollees without gaining a commensurate increase in lower-income members. Investors should watch for the following signals. Confirmation would come from a legislative proposal in a non-expansion state to expand Medicaid or a bipartisan bill that extends premium subsidies with lower income thresholds. Weakening would come from a clean extension of enhanced subsidies without changes or a federal ruling that limits Medicaid expansion flexibility. The Gangopadhyaya and Kaestner paper does not predict policy outcomes. It provides a measurement framework. The efficiency gap it identifies shifts the burden of proof onto those who argue for continued premium subsidies at current levels. For investors, the question is whether lawmakers adopt that framework or ignore it.