NEW YORK, Dec 4 (Reuters) - Brian Thompson, the CEO of UnitedHealth's (UNH.N), opens new tab insurance unit, was fatally shot on Wednesday morning outside a Midtown Manhattan hotel in what appeared to be a targeted attack by a gunman lying in wait, New York City police officials said.

The shooting occurred around 6:45 a.m. ET (1145 GMT) outside the Hilton on Sixth Avenue, where the company's annual investor conference was about to take place. Thompson was rushed to a nearby hospital, where he was pronounced dead. Police said the gunman remains at large.