Page 5 from the CBO H.R. 1628 American Health Care Act of 2017
CBO and JCT expect that, as a consequence, the waivers in those states would have another effect: Community-rated premiums would rise over time, and people who are less healthy (including those with preexisting or newly acquired medical conditions) would ultimately be unable to purchase comprehensive nongroup health insurance at premiums comparable to those under current law, if they could purchase it at all—despite the additional funding that would be available under H.R. 1628 to help reduce premiums. As a result, the nongroup markets in those states would become unstable for people with higher-than-average expected health care costs. That instability would cause some people who would have been insured in the nongroup market under current law to be uninsured.
https://www.cbo.gov/system/files/115th-congress-2017-2018/costestimate/hr1628aspassed.pdf