The worst week for Dow Jones Industrial Average and S&P 500 since 2008 financial crisis (Oct 2008).
Fed cut rates to near-zero the weekend before, lowering federal-funds rate to a range between 0% and 0.25%.
Dots to connect: QE, easing from central banks around the world, inflation on the way, bond issuing in low-interest-rate environment, another round of asset bubble(?) when recover, etc.