In October 1987, after a week in which the Dow Jones Industrial Average fell almost 10%, CNN reporter Dan Dorfman, speaking from the floor of the New York Stock Exchange, assured viewers we had seen the worst of the Wall Street carnage. “I can tell you that from here, the market is going up, up, up.”

On the following trading day, the Dow dropped another 22%, still the largest one-day percentage decline in the history of the index. From August to October that year, the Dow collapsed from 2,700 to 1,700. To put that in perspective, imagine if the Dow dropped from 40,000 to 25,000 today.

A week after the Crash of 1987, I was a 24-year-old newly-minted MBA, meeting with a client, advising him to move some of his retirement account assets into stocks. This elderly client, almost 50-years-old at the time, was quick to tell me that for 20 years, the Dow always eventually retreated below 1,000, and he was going to wait for the market to finish its fall from 1,700 to 1,000 before buying any stocks.

It never happened. By the end of the year, the Dow had rebounded to almost 2,000, creating a weird anomaly where the U.S. stock market produced a positive return in the same calendar year it experienced its worst single-day percentage decline.

That (former) client, now 86-years-old, lived to see the Dow increase from 1,000 to 40,000. I assume he eventually put some money in stocks, although that’s just a guess.

I thought about 1987 when, buried in the news about the Republican National Convention, the Dow Jones Industrial Average closed above 40,000 every day that week. A decline similar to the 1987 peak-to-trough drop would see the index fall from 40,000 to about 25,000.

How would you react if that occurred?

I fear that most people would initially blame their political bogeyperson of the week. If the stock market prefers one political party to the other, you couldn’t prove it by the last 15 years.

A smaller majority – but still a majority – would likely convince themselves of some horrible Wall Street doomsday scenario, sell their stocks, and plan to wait for the Dow to retreat back below 10,000 before trusting Wall Street again.

And a minority of investors would see it as an opportunity to be opportunistic when others are being fearful and would be massive stock buyers.

Including 1987, I’ve experienced 4 times that the Dow declined 30% or more. I’m not predicting when, but I am certain that I will experience it again – likely multiple times.

And I am just as certain that I will see the Dow cross the 100,000 level.

David Moon is president of Moon Capital Management. A version of this piece originally appeared in the USA TODAY NETWORK.