As the graph shows, the dollar has been increasing in value as sovereign credit problems around the world led investors to seek a safer currency in which to park cash reserves. Dubai and Greece have highlighted the risks of investing in a country with crushing debt. Caterpillar avoids most of the risk that comes with foreign-currency transactions, but there is still a component to the share price that can be explained by these movements. As the dollar strengthens in the face of possible sovereign debt downgrades, expect Caterpillar to lag a bit. Thanks to diligent hedging, however, investors should be more insulated from the move than companies like Coke are. -- Reported by David MacDougall in Boston.