Blue Shield of California has the largest number of enrollees in the Covered California health insurance exchange, widening its lead over rivals Anthem Blue Cross and Kaiser Permanente, according to recently released data.

The data, from Covered California, show that Blue Shield had 389,480 enrollees in the exchange as of December 2016, about 31 percent of the market. Anthem was next with 310,690 members, for a 25 percent share. Kaiser Permanente was third with 297,030 exchange enrollees, or 24 percent. Health Net and Molina Healthcare were fourth and fifth, respectively. (Kaiser Health News, which produces California Healthline, is not affiliated with Kaiser Permanente.)

This month, health insurers filed their proposed rates for next year with Covered California. After negotiations with the insurers, exchange officials are expected to announce the 2018 rate increases in July.