Central bank balance sheets have surged around the world during the pandemic

The Fed has not been alone in its unprecedented intervention in the U.S. economy during the pandemic. Central banks around the world have been printing money out of thin air and using it to purchase assets in order to stimulate their respective economies.

The big picture: Just the world's four largest central banks had accumulated $28.8 trillion of assets as of February, according to data collected by Yardeni Research.

What's next: "For central banks, I don’t think there is any alternative to what they’ve been doing until now, namely vastly significantly support the economy," former European Central Bank president Mario Draghi told Axios in December.

• "Support, in my view, will continue for quite a long time."