Maybe it's because the report looked good on the surface, but as the analysts looked at it, slightly disturbing items showed up - like the modest earnings projections. Probably some trading factors, too. I just bought some more on the idea that UNH - after a sort of nasty correction - is now low or at least fairly priced. E.g., 18 x 3 = 54.
UNH gapped up this morning because specialists and MMs are crooks and the specialist had to open up in order to have enough cheap shares to short -- knowing the book showed a big downdraft for today. Then he'll cover when enough of the inevitable shorters who come too late to the party -- and voila! The specialist or MM makes another killing on the bounce back up.