Several European central banks - the European Central Bank, Danish National Bank, Swiss National Bank and Swedens Riksbank - cut key interest rates below zero in 2014, and in Jan 2016 Japan followed. They tried to increase lending, spur inflation and reinvigorate the economy after other options have been exhausted.

Read the following articles and discuss some of the potential danger of the negative interest rates.

Negative Interest Rates, Bloomberg, June 2016

Here's Why Negative Interest Rates Are More Dangerous Than You Think, Fortune, March 2016