A hot topic this weekend has been whether we’re in for a Black Monday-style crash following Friday’s aggressive selloff.
For those unfamiliar, Black Monday refers to October 19, 1987, when the S&P 500 plunged over 20% in a single day—still the largest one-day drop in market history. This has fueled the old Wall Street saying:
“The market never bottoms on a Friday.”
The implication? A big selloff on Friday often leads to another rough session on Monday. But does history actually back this up?
Let’s look at the data:
Friday, February 21, 2025 – The S&P 500 dropped 1.71%, marking the 590th worst day in the market since 1970.
What happened historically after similar declines?
The next day, the market was positive 53% of the time
Average return: +0.11%
Median return: +0.12%
Hardly the makings of a disaster.
What about big Friday losses specifically?
Since 1970, there have been 122 Fridays with losses of at least 1.71%
The following Monday, the market was positive 55% of the time
Average return: -0.33% (skewed heavily by Black Monday)
Median return: 0.12%
Now, let’s zoom in even further:
What happens when a big Friday drop occurs near all-time highs (like now)?
This has happened only eight times since 1970.
The following Monday was positive 63% of the time
Average return: +0.2%
Median return: +0.3%
The takeaway?
I hate to break it to the bears, but history just doesn’t support the idea of a Black Monday-type event today. Sure, anything can happen in markets, but fear-based narratives don’t always align with reality—especially when we’re still near all-time highs.
Fear sells. But as investors, our job is to separate fear from facts and stick to the plan.
