I closely track gold flows reported by two big gold holders: IAU and GLD. 

However, there is a big difference between these two investment vehicles. Look at the charts below:

Green bars depict monthly flows of gold and red lines depict cumulative gold flows.

It is easy to spot that this year investors participating in IAU were accumulating gold (the up sloping red line) while those using GLD were doing the opposite (and as of August 21 GLD reported a year-to-date outflow of gold).

Now the question is: which gold vehicle gives more reliable signals – IAU or GLD?