S&P 500 Movers: HFC, ALXN

In early trading on Monday, shares of Alexion Pharmaceuticals topped the list of the day's best performing components of the S&P 500 index, trading up 6.6%.

Year to date, Alexion Pharmaceuticals registers a 5.4% gain.

In early trading on Monday, shares of Alexion Pharmaceuticals topped the list of the day's best performing components of the S&P 500 index, trading up 6.6%.

Year to date, Alexion Pharmaceuticals registers a 5.4% gain.

And the worst performing S&P 500 component thus far on the day is HollyFrontier trading down 4.8%.

HollyFrontier is lower by about 51.5% looking at the year to date performance.

Two other components making moves today are Baker Hughes, trading down 3.6%, and DISH Network, trading up 4.2% on the day.