Plot price history UDN with FXE, they're nearly identical. Correlated I could understand, but TRACKING one another seems to ignore all other currencies in the dollar basket. Any reason for this?
I can see the same mismatch with the 2X short 20yr US bonds. If you plot the TLT (10yr) vs the TBT you will see the same thing. The % moves are 98% correlated yet they track two different securities.