S&P 500 Movers: NOV, ADT

In early trading on Wednesday, shares of ADT Corp (ADT) topped the list of the day's best performing components of the S&P 500 index, trading up 8.0%. Year to date, ADT Corp has lost about 18.3% of its value.

And the worst performing S&P 500 component thus far on the day is National Oilwell Varco (NOV), trading down 10.9%. National Oilwell Varco is lower by about 18.4% looking at the year to date performance.

Two other components making moves today are Marathon Petroleum (MPC), trading down 6.8%, and Avery Dennison Corp. (AVY), trading up 7.2% on the day.