S&P 500 stock market values are experiencing the same volatility as the first half of 2020, the start of the Covid-19 pandemic (based on the 50 largest value movements as a percentage of the index’s total market value). These dramatic movements show that market volatility leads to big price movements in stocks, both up and down. There are a couple of factors combining to enhance this turbulence: The popularity of the momentum trade (buying stocks that are rising quickly and dump the relative losers quickly). Decreasing liquidity (fewer buyers and sellers for the other side of trades). Both factors magnify the market’s moves in either direction.