The mystery, in a nutshell, was as follows: while banks are printing more bank notes than ever, these seem to be "disappearing off the face of the earth" and nobody knows where or why, or as the WSJ notes, "central banks don't know where they have gone, or why, and are playing detective, trying to crack the same mystery."

And while readers can read up much more on the topic of disappearing hard assets here, a few days after, Fox Business picked up on this thread, writing that almost $1.5 trillion of the world's physical cash, with $100 dollar bills making up the vast majority, was reportedly unaccounted for.