In times of crisis, cash is king. People flee from risk and try to buy risk-free assets. Treasury bills (T-bills) are considered as safe as cash, but pay interest. As people have fled risk, they have demanded more T-bills, driving up their price and driving the interest rates down.
The U.S. Treasury reports the daily interests rates on its debt, and the drop in the interest rates on the short-term debt is quite remarkable. In the early part of September, the interest rate on 1 month debt was very low but still above 1%. Since September 12, it has been below 1%, dropping all the way to .07% on September 17. If you invest $1000 at .07%, for a year, you will earn 70 cents interest. On September 19 it was up to .76, but today it was back down to .16%.
You can see the drop in interest rates in the maturities through the 7-year mark, but it is pretty hard to see anything in the 10-year securities.
The data are currently here, but will be moved here in a few days, and in a few months it will probably be here.
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