"[It] is important to better understand how different regulatory environments may affect the functioning and competitiveness of insurance markets. In the case of rate review, a recent study suggests that pre-ACA premiums were lower in states that took a more active regulatory approach.... On the other hand, an NBER working paper argues that state regulatory backlash against managed care during the late 1990s increased health spending by a non-trivial amount. State regulatory action, therefore, has the potential to both increase and decrease costs for consumers."