Shares of UnitedHealth Group (NYSE: UNH) were pulling back Thursday after the company delivered underwhelming fourth-quarter results, as sales were weaker than expected and its costs rose. Revenue in the quarter rose by 6.

UnitedHealth is putting pressure on the 30-stock index Thursday after the insurance giant reported a rare revenue miss. This is what you need to know.

Adjusted per-share earnings in the fourth quarter for UnitedHealth top analysts’ estimates but revenue comes up short.

But high medical costs contributed to results that disappointed Wall Street, and the company’s stock fell on the news that it had made less than analysts expected.

UnitedHealth Group recorded slightly higher earnings in the fourth quarter, though its sales gains fell short of analyst projections.