In his first public comments since one of his executives was shot to death, UnitedHealth Group CEO Andrew Witty said the healthcare system “needs to function better.”

In its first results since its insurance unit CEO was fatally shot in New York City, UnitedHealth Group reported Thursday weaker-than-expected fourth-quarter revenue, prompting its shares to fall in early morning trading despite quarterly profit beating projections.

UnitedHealth's fourth-quarter revenue missed Wall Street estimates on weakness in its health insurance business and the company also reported higher-than-expected annual medical costs, sending its shares down nearly 5% before the bell on Thursday.