If you hadn't been paying attention, you might think 2020 has been a boring year for stocks. Prior to last Thursday's sell-off, the S&P 500 was flat for the year, having recovered almost all of its coronavirus-related losses. Of course, it's been anything but boring. Stocks lost more than a third of their value in February-March, only to then soar 47 per cent. Thursday's sell-off was a reminder the rollercoaster ride isn't over yet. Things have been even hairier for stock-pickers. At March's market bottom, 156 companies in the S&P 500 were down by at least 40 per cent, notes Ritholtz Wealth Management's Ben Carlson, compared with just 22 last week. More than 17 per cent of stocks had halved; last week, fewer than 1 per cent were in that position. Research shows investors who don't look at their portfolio outperform those who do, and little wonder; following these kind of market swings would make the hardiest investor nauseous.

This has been the fastest stock market in history, notes Carlson's colleague, Michael Batnick, and one lesson to take away is that "just staying on the course is more important than perfecting the journey".