[Pontiac]

Those are Prime Interest Rates. The rates on money the Central Banks loan to Commercial Banks.

That is not the rate on Treasury Bonds or Bills which is the way governments borrow money.

[grey_whiskers]

Read the whole article.

https://www.cnn.com/2020/01/23/investing/switzerland-cash-negative-rates/index.html

Some of the commercial banks have passed on negative interest rates to their customers.

Counterexample of the real-world existence of negative interest rates, complete.