UnitedHealth Group's profit in the first quarter of 2018 soared 31% year over year, totaling $2.84 billion. Revenue jumped 13% in the quarter, to $55.2 billion.

The big picture: UnitedHealth, arguably the most dominant conglomerate in the health care industry, raked in more money across all of its different businesses and benefited from the lower corporate tax rate. Private Medicare Advantage growth fueled its health insurance division, while its pharmacy benefit manager, doctor practices and data technology boosted its services division, called Optum.