The Affordable Care Act will make the labor supply, measured as the total compensation paid to workers, 0.86% smaller in 2025 than it would have been in the absence of that law, the Congressional Budget Office estimates. Three-quarters of that decline will occur because of health insurance expansions, which raise effective tax rates on earnings from labor—for instance, by phasing out health insurance subsidies as people’s income rises—and thus reduce the amount of labor that workers choose to supply.