After Trump announced comprehensive tariffs, U.S. stocks fell 10.5% in two trading days. Former U.S. Treasury Secretary Summers posted on X on Saturday that since World War II, the S & P 500 has performed worse for two consecutive trading days than after Trump announced tariffs, only in the stock market crash of 1987 (26.4%), the financial crisis of 2008 (12.4%) and the COVID-19 pandemic outbreak (13.9%).