The largest health insurer in the U.S. fired on all cylinders in 2019, with a 7% increase in annual revenues that brought the company's haul to $242 billion. Its UnitedHealthcare division grew by $10 billion last year, but the insurer's real and not-so-secret weapon continues to be its Optum unit, which provides an array of health care services including data analytics and pharmacy benefits management. Optum revenues climbed 12% year-over-year, to $113 billion. UnitedHealth Group also has considerable ambitions for its Medicare Advantage business, which had its best-ever enrollment last year, adding 325,000 elderly Americans.