To investigate how changes in insurer participation and composition as well as state policies affect health plan affordability for individual market enrollees.
2014‐2019 Qualified Health Plan Landscape Files augmented with supplementary insurer‐level information.
We measured plan affordability for subsidized enrollees using premium spreads, the difference between the benchmark plan and the lowest cost plan, and premium levels for unsubsidized enrollees. We estimated how premium spreads and levels varied with insurer participation, insurer composition, and state policies using log‐linear models for 15 222 county‐years.
Increased insurer participation reduces premium levels, which is beneficial for unsubsidized enrollees. However, it also reduces premium spreads, leading to lower plan affordability for subsidized enrollees. States responding to cost‐sharing reduction subsidy payment cuts by increasing only silver plans' premiums increase premium spreads, particularly when premium increases are restricted to on‐Marketplace silver plans. The latter approach also protects unsubsidized, off‐Marketplace enrollees from experiencing premium shocks.
Insurer participation and insurer composition affect subsidized and unsubsidized enrollees' health plan affordability in different ways. Decisions by state regulators regarding health plan pricing can significantly affect health plan affordability for each enrollee segment.