30 years ago today, global stock markets collapsed. The U.S. stock market represented by the S&P 500 had gained over 35% year-to-date. Investors were likely optimistic. It only took a single day to erase the gain.
The loss on Black Monday was -31.5%. Notice that a -31.5% decline more than erased a 35%+ gain. In fact, after the index had gained over 35% for the year, it was down nearly -9% after a -31% decline.
Below we see it in action. It only took a decline of -31% to erase over 60% of a 100% gain since 1984. The S&P 500 stock index had gained over 100% since 1984. The -31% decline brought the gain all the way down to 37%. Losses are very asymmetric.
Black Monday is talked about as a single one-day event, but really it wasn’t. Several weeks of weakness led up to a big down day. But, it would have taken a rather tight risk management system to have exited.
Looking even closer, the % off high chart shows the stock index was about -7% off its price high for several weeks before the crash. So, a drawdown control and risk management system trading this index would have had to exit because of this trend.
It doesn’t have to happen in a single day to erase a lot of gains.
Let’s remember this one.
And more recently, this one.
Today is a reminder that markets are risky and they necessarily require risk management.