September has witnessed many economic disasters and financial wars throughout history that left deep imprints on the global economy, most notably the Wall Street Crash in 1929, the subprime mortgage crisis in 2008 that caused a global recession and the bankruptcy of many major financial institutions, the oil crisis in 1973 that caused a shock in global energy prices, and the European sovereign debt crisis in 2011 that threatened the stability of the Eurozone, World War II began in September, and the Gulf War in September, the events of September 11, all of this made investors, speculators and most US traders describe September as the month of disasters, and for this reason most tend to exit the market, taking advantage of the summer vacation, which makes liquidity in the market low and therefore random trading controlled by the herd that is dominated by emotion.