Gold's decade long bull run from 2001-2011 was predicated upon two primary supporting trends:

1. A falling US dollar and a growing global distrust and waning confidence in the greenback as the world's reserve currency.

2. Falling US Treasury yields and negative real interest rates throughout much of the developed world.

While there are certainly a multitude of lesser factors which contributed to the bull market in gold, historically low interest rates and a weak US dollar were the key underpinnings to gold's 650% rise over the last decade. During 2013 the US dollar index has risen over 7% and the 10-year US Treasury yield has jumped more than 100 basis points since early May - there is no coincidence that 2013 has been a terrible year for gold:

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Gold_vs._USD_-_USTs