CDW is a Fortune 500 company at #270 in that list

http://money.cnn.com/magazines/fortune/fortune500/2012/full_list/

Since being purchased by a private equity firm in 2007 CDW has been off the Fortune 500 list (only for publicly held companies), but the way CDW is now trading its debt and other items in a latest SEC filing, they are re listed again.  

They moved up 72 positions since 2007.  They also changed from being listed as a wholesaler to an Information Technology Services company in the Fortune list.