The Oxford English Dictionary defines “volatile” as “liable to change rapidly and unpredictably especially for the worse.” It's not as if investors don’t know what that’s like -once again over the past week global stock markets were subjected to extreme fluctuations. The red line in the chart below shows the daily percentage change in the S&P 500 illustrating the severe movements seen in the stock markets in recent times. Click here to enlarge.Turbulence was rife as more data showed the world economy facing an even longer and more intense downturn than many feared. Battle-weary investors were also spooked by continued ...