There is an old joke about economists: They are people who see something working in practice and try to figure out if it would work in theory. Just recently we have seen an example of this when interest rates on US Treasury bills turned negative, meaning the US federal government got paid for borrowing money rather than paying to do so.

In theory, this isn't supposed to happen. If market interest rates are negative then people normally just hold on to their cash. But these aren't normal times. The fear of risk is so pervasive that individuals and businesses don't trust even cash and are willing to pay a premium to park their money in Treasury bills.

This explains a great deal about what is at the root of the economy's problem today. People are so risk-averse that they are hoarding money, refusing to spend; banks are refusing to lend even to their best customers; and businesses are so desperate for safety that they would rather get a negative return on a safe asset than invest in something remotely risky, no matter how high the potential return.