Stocks experienced one of their worst starts to September in history, with the SPDR S&P 500 (ARCA:SPY) being particularly affected. The reason for this decline can be attributed to various factors impacting the market. Investors were concerned about economic uncertainties, geopolitical tensions, and the ongoing trade war between the US and China. These uncertainties led to a lack of confidence in the market, causing stocks to plummet. It is important for investors to stay informed and monitor market conditions closely during times of volatility.