On Friday, the California's Department of Insurance approved a rate hike for Aetna. Under the plan, average premiums will go up 19 percent. The maximum increase would be 30 percent.
California's three other large insurers, Anthem Blue Cross, Blue Shield, and Health Net were allowed to move forward with similar increases last month.
Combined, the four companies control 90 percent of the state's individual policies.
All of the rate hikes are scheduled to take effect on October 1.