CNBC reports that there has been a “mysterious surge in $100 bills” around the world.

Currently, there are more than 12 billion US $100 bills in circulation, double the number from a decade ago; and $100 bills now outnumber $1 bills.

General consensus among economists seems to be that the influx is due to the global hoarding of money. However, history also says that high-denomination currency is preferred by criminals.
DataTrek Research co-founder Nicholas Colas says the surge has nothing to do with the US economy. He points out that, while there is indication it “is an enabler of corruption,” the number of $100 bills overseas began rising following the Gulf War and US invasion of Afghanistan as a replacement to local currencies was need to stabilize the region.