Originally posted by rpm 
So tax breaks for big corporations are not a form of subsidy? 
 See the first line of my reply to john and replace jon with rpm
Then add:
tax breaks have the tendency to keep corporations in certain areas.  While I do not always agree with it, I can see the value in keeping corporations in certain areas to prevent mass unemployment if they leave.  
One more thing, subsidies have a tendency to go to individual families that benefit only that family that receives thesubsidy.  Tax breaks benefit a corporation AND a community / area.