The approximate value in US$ of the world gold market capitalization is 11.846 trillion US$.
This calculation has been made estimating the total amount of gold above ground, which is about 201,296.1 metric tonnes. The current price of gold is 1668.30 US$/ounce and there are 35274 ounces in a metric tonne.
Here is a chart that shows the gold market capitalization each year since 2010
Source of the chart
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