Markets have been getting more volatile for weeks, making these days more frequent. Japan's stock market fell 12.4% today. This is partly because the yen strengthened 10% in the last month, which means Americans will not want to buy treats from Japan because they are more expensive. They also thought Jpow would let us have low interest rates again and he did not, so they also think we will not buy Japanese treats because we won't have jobs. The Japanese stock market is the 3rd largest in the world. Big losses on a big market will spread because everything else will get sold to buy the Japanese dip. It's also going to cause monetary contraction because of levered speculation. Large amounts of money is called into existence to buy stocks and that fuels demand in the real economy, and when those stocks go down, the loss in equity is large, stocks are sold at a loss to repay the borrowing, contracting the money supply and lowering buying power and demand across the whole market. But one never knows when it will stop.