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.

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 beat fourth-quarter earnings forecast, though revenue fell short and medical costs ran high, hitting the Dow Jones component.

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