Seventy-three percent of U.S. health insurance markets are highly concentrated, based on guidelines used by the Department of Justice and Federal Trade Commission to assess market competition, according to a study released recently by the American Medical Association. In 91 percent of the 380 metropolitan statistical areas studied, at least one insurer had a commercial market share of 30 percent or more, and in 46 percent of MSAs a single insurer’s share was at least 50 percent. “Our findings should prompt federal and state antitrust authorities to vigorously examine the competitive effects of proposed mergers between health insurers,” the report concludes. North Carolina is 6thin the Top 10 states that experienced the largest decrease in competition levels between 2016 and 2017. North Carolina is 10th in the Top 10 states with the least competitive commercial health insurance markets. More details are online here.