Planet Money : NPR
Since the pandemic hit, the amount of paper dollars in the world has actually increased. There is now $2 trillion in paper dollars out in the world — roughly $200 billion more than there was at the start of the year. This bump was partly driven by pandemic panic, but not entirely. For years, as our daily use of cash has declined, the amount of paper money floating around has grown faster than the overall economy. And it's largely hundreds. There are more $100 bills than ones — enough to give every person in America $4,000 in hundreds.
Where is all that money? What are people doing with it? Nobody knows exactly. It's just pieces of paper out in the world! But we do have some ideas. People in developing countries are keeping their life savings in hundreds to protect themselves against unreliable local currencies and shaky banks. Also, lots and lots of people are using lots and lots of cash to evade taxes and to traffic in drugs, people and stolen merchandise.