Why would a central bank want negative interest rates?

4:00 PM ET Wed, 25 Sept 2019

President Donald Trump is a big fan of low interest rates. In fact, he's called on the U.S. Federal Reserve to take rates into negative territory, just like Germany or Japan. In theory, the banks would pay you to borrow money. But savers would also have to pay a bank to keep their money there. So why would President Trump or a central bank want negative rates?