The third annual tally of the greenest corporations in the United States and the world brings an overhauled methodology to the list and finds a new U.S. leader, with IBM replacing Dell in the top spot, and HP holding its second place rank.

The third annual tally of the greenest corporations in the United States and the world brings an overhauled methodology to the list and finds a new U.S. leader, with IBM replacing Dell in the top spot, and HP holding its second place rank.
