The 10 biggest health insurers in California are listed below, ranked by market share according to the latest data available from the National Association of Insurance Commissioners in early 2011. Rank Insurer #1 Kaiser Foundation Health Plan, Inc. #2 Blue Cross of California #3 Health Net of California, Inc. #4 California Physicians’ Service #5 Pacificare of California #6 Anthem Blue Cross Life & Health Ins. Co. #7 Delta Dental of California #8 Aetna Health of California, Inc. #9 Unitedhealthcare Ins. Co. #10 Aetna Life Ins. Co.   Source:  US Health News