An impressive $13.4 billion was poured into gold assets over the past 11 weeks, according to Bank of America Merrill Lynch. That's the largest sustained weekly inflow for gold since during the 2009 financial crisis.

Gold is considered a safe asset that tends to rise in demand when people are worried about the economy or fear inflation. Gold skyrocketed earlier this year amid concerns of a recession and bear market in stocks. Gold is up 15% to $1,221 an ounce in 2016, crushing stocks and bonds.

The fact that investors are still betting big on gold is interesting since markets have calmed down considerably. Recession fears have receded, and oil prices have stopped crashing. The Dow is up about 2,000 points from its February 11 low and recently turned positive on the year.

All of this suggests "uncertainty about the future and a concern that some nasty surprises might lie ahead," Barclays analyst Kevin Norrish wrote in a recent report.