美股什么时候抄底？In a dataset dating back to 1928, returns of -4% or worse for the S&P 500 have only occurred 146 times. Since the end of World War II, we have only seen 51 days this weak in 75 years. Down 4% days are rare, and they tend to cluster in economic recessions. Putting together the cumulative weak days on Monday, Tuesday, and Thursday and we are entering historic territory. The S&P 500 has shed 10.7% over these past four trading sessions. . We have not had a four day selloff this bad since the financial crisis in 2008. (-17.2% in four days ending October 9th, 2008) . Before that, we had not experienced as bad of a 4 day stretch since July 2002 when the announcement of accounting regularities at Worldcom spooked a market already grappling with the tech bubble deflation and post-9/11 uncertainty. (-11.96% in four days ending July 23, 2002) . Before the 2002 sell-off, it was the worst four day period since August 1998 when global assets were frightened by the prospect of a Russian debt defaul (more...)