Stocks are making their most extreme moves in 20 years — and one quant expert says the COVID-19 crash was a preview of more 'wild swings' to come

· Stock-market moves that stray far from the norm are at a 20-year high, according to quantitative strategists at Societe Generale. 
· The Federal Reserve's growing interventions in markets, and lower liquidity, are among the reasons why so-called fat tails have grown larger. 
· The quants expect that "wild swings" will...