Central banks speed up their printing -> global markets have higher returns.
Central banks slow down their printing -> global markets have lower returns.

Simple as that. In other words financial market returns are (mostly) achieved by newly created money supply that turns into increased stock prices and later on when gains are collected, burden is thrown down on everyone as a hidden tax (so called needed inflation). This can continue only as long as productivity grows to cover it. If productivity stagnates middle-class goes into poverty, socialism is triggered and it all ends with riots and blood in streets. Those who are running this systemic crime (politicians, central bankers and big bank bankers) remain (as usually) unpunished.