The stock market crash of 1987, referred to as Black Monday, differed from previous collapses in that it occurred over a very short period of time. Worldwide indices experienced the largest one day decline in stock market history.

Overseas markets were hit first with Hong Kong and Australia realizing the largest declines.

Primary causes of Black Monday remain under debate. Most economists agree that the soft landing experienced in the late 80's/early 90's, following a period of rapid growth in the mid-80's, was forecasted and reflected in the precipitous drop in equity prices during the '87 crash.

Some blame program trading, where computers execute rapid transaction, causing a chain reaction that would spark a domino selling effect. Others site overvaluation and market psychology for the crash, stating inflated asset prices caused selling pressure that would escalate as more traders followed the herd sentiment.

The '87 crash is often the reference point for subsequent stock market declines as it reflects a more accurate comparison to current market conditions than the '29 or '73 events.

Stock Market Crash of 1987 - Black Monday - Article By Better Trades