I think the powerhouse economies have been doing so well (hello QE), that people can become a bit wary, so many profits to be taken in equities, the money pile grows, it's gotta go somewhere, safe haven buying? Just a guess but if folks are taking profits out of equities but the currency is falling in value where you going to go? Bonds are crap.. Last year was 2nd highest inflows into gold ETF, prior was 2009. Private Gold demand fell a bit 4th quarter 2016 yoy, hmmm, less disposable income?
China gold buying also at a 4 year high, central banks continue to hoard.