The federal tax reform act of December 2017 eliminated the penalty for noncompliance with the Affordable Care Act’s (ACA) individual mandate (also known as the shared responsibility requirement) starting in 2019. This legislative change has highlighted uncertainty about the penalty’s importance in inducing lower-risk individuals to purchase insurance, and the potential for higher premiums in the individual insurance market should they not do so.
Hsu, John, Vicki Fung, Michael E. Chernew, Alan M. Zaslavsky, William Dow, and Joseph P. Newhouse. "Eliminating the Individual Mandate Penalty in California: Harmful but Non-Fatal Changes in Enrollment And Premiums." Health Affairs, March 1, 2018.