Page 31

How Initial Conditions Can Have Permanent Effects: The Case of the Affordable Care Act

We document that states that experienced website glitches in the ACA's first year faced higher average costs that persisted into future years. These dynamics are inconsistent with the standard strategic-pricing model, which requires non-localized common knowledge about market conditions, but are consistent with price-taking. Initial conditions can have a permanent effect—including convergence to a Pareto-dominated, stable equilibrium—under conditions that we show are plausible in this setting. Changing the fine from a fixed amount to a fraction of equilibrium prices increases the likelihood of reaching a Pareto-efficient equilibrium without increasing the equilibrium fine collected.