The lower interest rates are, the more attractive it is for companies to invest and for people to consume. Demand goes up and so do prices. The ECB entered unfamiliar territory in June 2014 when it reduced the deposit rate for banks to below a level previously regarded as a barrier: the “zero lower bound”, as it is called.
A slow economic recovery and persistently low inflation had made that necessary. Banks are therefore now having to pay interest on their deposits at the ECB. It may seem strange to many people to have to pay someone you’re lending money to.