Catholic Health Initiatives and Dignity Health have agreed to merge into the nation's largest not-for-profit health system, pending antitrust and church approval. The combined health system will create new headquarters in Chicago and rename itself by next year.

Why it matters: The merger has been in the works for months and will create a behemoth not-for-profit, Catholic-based system that will own 139 hospitals in 28 states and control more than $28 billion of revenue — making it bigger than companies like McDonald's or Macy’s.

Context: CHI and Dignity have been losing money on patient care, but have reaped big gains from Wall Street, like other not-for-profit giants. The merged system likely will strip out costs and gain negotiating power over private health insurers.