Based on the following below:
US has 8133 tonnes of gold.
Gold medal price is $1755.15 per ounce.
There are 32,000 ounces in one tonne.
8133 x 32,000 = 260,256,000 (ounces the US owns)
260,256,000 x $1755.15 = $456,788,318,400.00
The US owns $456,788,318,400.00 worth of gold.