Estimated National Market Shares of the Four Largest Insurers

Notes: This exhibit is constructed using the number of privately insured lives reported in each insurer’s annual reports. Consistency over time and across insurers in terms of products included is not assured. BCBS share (exclusive of Anthem) is estimated using enrollments reported by BCBS for 2010 and 2014, and extrapolating back to 2006 by applying the growth rate in BCBS enrollments from data supplied by the National Association of Insurance Commissioners (NAIC), and corrected for states not reporting or underreporting BCBS enrollment. The BCBS association reports total enrollment of 100 million in 2010 and 106 million in 2014 and may include noncomprehensive insurance. Unfortunately, NAIC reflects only fully insured plans outside of California, whereas this exhibit includes both full and self-insurance for all states. Anthem operates BCBS affiliates in California, Colorado, Connecticut, Georgia, Indiana, Kentucky, Maine, Michigan, Nevada, New Hampshire, New York, Ohio, Virginia, and Washington. National market size in each year is the number of privately insured lives, as estimated from the Current Population Survey.

Data Source: Current Population Survey, “Total People with Private Health Insurance, 2002–2013,” available at

Source: The Commonwealth Fund: Evaluating the Impact of Health Insurance Industry Consolidation: Learning from Experience