From Coinpedia · By Anjali Belgaumkar
“Black Monday” is trending on social media ahead of Wall Street’s open on October 19, 2026, the 39th anniversary of the worst single-day crash in stock market history. Weekend liquidations in tokenized AI stocks, high oil prices and rising bond yields are behind the talk.
What Happened On Black Monday In 1987
On October 19, 1987, the Dow Jones Industrial Average fell 22.6% in one session. It is still the largest one-day percentage drop on record, worse than any day of the 1929 crash, the reopening after the September 11 attacks, or the 2008 financial crisis.
The S&P 500 lost 20.5% and the Nasdaq 11.4% that day.
About $500 billion in US stock value was wiped out.
Hong Kong closed its stock exchange for four days. When it reopened, the Hang Seng fell 33%.
The Federal Reserve said it would provide liquidity to keep the financial system running.
Why Markets Crashed
There was no single cause. At the time, reports blamed rising tensions in the Persian Gulf, fears of higher interest rates, worries about the trade deficit, computer-driven program trading, and a five-year bull market that had gone without a meaningful correction. Coverage that evening kept returning to one word: panic. Once fear took over and orderly trading stopped, selling fed on itself.
The Brakes Wall Street Added Afterwards
US exchanges introduced circuit breakers in 1988. Under today’s rules, trading pauses based on how far the S&P 500 falls:
7% drop before 3:25 pm ET: all US stock trading halts for 15 minutes
13% drop before 3:25 pm ET: a second 15-minute halt
20% drop at any time: trading ends for the day
According to CME Group, S&P 500 futures are also limited to a 7% move overnight. The breakers first triggered on October 27, 1997, when the Dow fell 554 points and trading closed 30 minutes early. Regulators tightened the rules in 2013, after the breakers failed to trigger during the 2010 Flash Crash. In March 2020, the first-level halt tripped four times in eight trading days. The 20% level has never been hit.
Why Traders Fear A Repeat On October 19
Brent crude reportedly closed Friday near $110, partly linked to reports of Ukrainian strikes on oil facilities near St. Petersburg.
The VIX volatility index is said to be at a four-month high.
Treasury yields are rising, and inflation is running hot.
Bank stocks fell, and unconfirmed rumours about trouble at an AI-focused fund are spreading.
Crypto entrepreneur Ran Neuner said $1.9 trillion has been wiped from US tech stocks.
Fund manager Adrian Day said that some of today’s conditions resemble 1987, including higher rates, concerns about the dollar and deficit, and an AI sector many consider overvalued. However, he said yields are not yet high enough to pull large amounts of money out of stocks and into long-term Treasuries. He added that the most recent 10-year auction was well bid.