What it means
After several years of rising share prices, markets were already nervous in the days before the crash. On the Monday, a flood of sell orders hit exchanges first in Asia, then Europe and then the United States.
Prices fell faster than traders could process, and many could not even reach their brokers by phone. Several causes are usually cited.
Investors worried about high valuations, rising interest rates and a weak dollar. A popular strategy called portfolio insurance, in which computer programs automatically sold stock futures as prices fell, is thought to have made the selling worse because it pushed prices down further and triggered more selling.
The crash was sudden but its economic damage was smaller than many feared. Central banks, led by the Federal Reserve, publicly promised to provide liquidity (ready cash) to the financial system.
Markets steadied over the following days and the broader economy avoided a deep recession. The episode changed market structure.
Exchanges introduced circuit breakers, which pause trading when prices fall by set amounts, to give participants time to think. Regulators reviewed clearing and settlement systems, and firms paid more attention to how automated strategies could feed on each other.
For business people, Black Monday is a reminder that markets can fall far and fast without a clear piece of bad news. It also shows how recovery can take time: it took roughly two years for the main US index to regain its pre-crash level.
Long-term investors who held on were rewarded, while those who sold in panic locked in their losses. The crash is also a reminder about liquidity.
In the worst moments, buyers disappear, bid prices collapse and orders cannot be filled at any sensible price. Firms that held enough cash survived the panic, while those forced to sell to meet margin calls (demands for extra collateral) made matters worse.
In practice
Real-world examples.
Example
A retail investor with $50,000 in shares sees her portfolio fall to $39,000 on the day. She resists selling because she does not need the money for ten years. Over the next few years her holdings recover and she adds new shares at lower prices. She later says that the decision to stay calm was the best of her investing life.
Example
A trading firm has an automated strategy that sells whenever prices drop by 2%. During a rapid fall, the strategy sells repeatedly and prices drop even further. After the event, the firm adds a rule that limits how much its programs can sell in a short period. Its risk committee also starts testing every strategy against a one-day fall of 20%.
Example
An exchange committee studies how orders overwhelmed its system on the day. It proposes circuit breakers that halt trading for fifteen minutes after a sharp fall. The proposal is adopted so that traders have time to assess the information.
Formula
Calculation
Percentage change = (Ending value - Starting value) / Starting value x 100
Gain needed to recover = (Starting value / Ending value - 1) x 100
Suppose an investor holds a $100,000 portfolio that falls 22.6% in a day, similar in size to the one-day fall in the Dow. Ending value = 100,000 x (1 - 0.226) = 100,000 x 0.774 = $77,400. To get back to $100,000 the portfolio must rise by (100,000 / 77,400 - 1) x 100 = (1.2920 - 1) x 100 = 29.2%. A fall of 22.6% therefore needs a gain of about 29.2% to recover.Case study
Seen in the real world.
Marsden Pension Fund is a fictional scheme that held $800,000,000 in shares when a sudden crash hit the market in a scenario similar to Black Monday. Within hours, the fund's value fell by $180,000,000, and some trustees urged an immediate sale of all shares.
The investment committee in this illustrative story met that evening and reviewed its long-term plan. It had enough cash and bonds to pay pensions for three years, so there was no need to sell shares at low prices. The committee held its position and used spare cash to buy more shares, and the fund recovered its losses within two years.
Watch out
Common mistakes.
- Believing a crash always signals a recession. Black Monday was followed by a recovery without a deep downturn.
- Selling in panic and locking in losses. Investors who sold at the bottom missed the recovery.
- Ignoring the maths of recovery. A 22.6% fall needs a gain of about 29.2% to get back to even.
Questions
People also ask.
What caused Black Monday?
Analysts point to high valuations, rising interest rates, trade and currency worries and automated selling, though no single cause explains everything.
How is Black Monday different from the 1929 crash?
The 1987 fall happened in a single day and was followed by a quick policy response, whereas the 1929 crash was part of a long slide into the Great Depression.
Could another Black Monday happen?
Markets can still fall sharply, but circuit breakers and better coordination make a repeat of the same pattern less likely.
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