I think it's the yen/dollar relationship and I think the Japanese are even more skittish about our economy than we are It's getting dragged down on the Nikkei. Whatever it is you can bet it's short term.
There's certainly no fundamental business reason. TM keeps reporting record profits. All indicators point to continued growth for TM.
Either that or Fungi the basher has single-handedly caused the drop with his brilliant insights he so regularly posts here. (NOT!) :)