Once the largest fund of its kind in the world, top physical gold-backed exchange traded fund – SPDR Gold Shares (NYSEARCA: GLD) – is having a rip-roaring first half of 2016.

GLD dwarfs other physically-backed exchange traded gold products holding 48.8% of the global total as of today at 950 tonnes or 30.5m ounces worth $40.3 billion. GLD's holdings have shot up by 308 tonnes this year to the highest since July 2013.