The biggest companies are seeking more cost efficiency and scale as the health-care landscape changes because of the Affordable Care Act and other factors. Of the current major health insurers, only UnitedHealth Group Inc., the largest by revenue, has so far sat out the merger wave. (Wilde Mathews and Hoffman, 7/24) The Associated Press: Why The 2010 Health Care Law Led To Insurance Merger Mania The health care overhaul law has reshaped the health insurance business, and one consequence is more than $100 billion in mergers and acquisitions over the last few years. Anthem Inc.'s purchase of Cigna Corp. and Aetna Inc.'s acquisition of Humana Inc., both announced this month, are worth more than $80 billion combined. The companies snapped up competitors in smaller, but still hefty, deals for years before that. (6/24) The Wall Street Journal: MoneyBeat: Insurer Analysts See More Deals, But No Feeding Frenzy Can the insurance mergers keep going?