Mario Molina, the CEO of Molina Healthcare. Michael Tullberg/Getty Images Republicans have unveiled their package to overhaul the Affordable Care Act, and at least one CEO of a health insurer is wary that the plan could lead to massive premium hikes.

In an interview with The Wall Street Journal, Mario Molina, the CEO of Molina Healthcare, predicted that the new AHCA would cause an increase in the cost of premiums for people in the individual insurance market.

Molina's firm provides a large offering of managed Medicaid plans for the government and is also active on the individual health-insurance exchanges set up by the ACA in nine different states.

In the interview with The Journal, Molina said premiums for the more than 12 million people in the individual insurance market could skyrocket by more than 30% next year. In 2017, the benchmark silver plan in the same market increased by 25%, which was decried by many GOP lawmakers, including President Donald Trump.

"You're going to see big rate increases, and you're going to see insurers exit markets … this is going to destabilize the marketplace," Molina told The Journal.

Molina Healthcare was also one of the most successful insurance companies on the Obamacare exchanges. Using its stripped-down plans modeled on Medicaid offerings, unlike other large insurers that modeled their plans on more expensive employer coverage, the company turned a profit on the exchanges over the past few years.