This news service caught up late last week with Dr Richard Smith, known in the industry as "The Doctor of Uncertainty." He is the chief executive of the investing tool looks the strongest.

What are the portfolio diversification and asset allocation lessons that wealth managers and private clients take from all this? 
Pay attention to Sharpe and/or Sortino ratios. When an asset fails to deliver rewards for risks, start trimming in the sails. Don’t succumb to anchoring bias. Just because NFLX was $690 in October 2021, doesn’t mean that it’s a bargain at $350 in April 2022. Increasing volatility has a cost. Pay attention to it. (A “Sharpe Ratio” is the average return earned in excess of the risk-free rate per unit of volatility or total risk. The Sortion ratio differentiates harmful volatility from total overall volatility by using the asset's standard deviation of negative portfolio returns – downside deviation – instead of the total standard deviation of portfolio returns.)

Who in particular needs to heed the lessons of the sell-off? Are risk management systems fit for purpose in this industry?”
Everyone needs to heed the lessons of this sell-off in the likes of FB and NFLX. Wiping out $50 billion of shareholder value in 12 hours should not be possible but it’s happening more and more regularly this year. Something is broken and everyone needs to be on high alert. Risk management systems are extremely useful, but they don’t allow you to keep your head in the sand. It’s a time that all investors have to be chopping wood and carrying water.