Black Monday (also known as Black Tuesday in some parts of the world due to time zone differences) was a global, severe and largely unexpected stock market crash on Monday, October 19, 1987. Worldwide losses were estimated at US$1.71 trillion. The severity sparked fears of extended economic instability or a reprise of the Great Depression.
Possible explanations for the initial fall in stock prices include a fear that stocks were significantly overvalued and were certain to undergo a correction, persistent US trade and budget deficits, and rising interest rates. Another explanation for Black Monday comes from the decline of the dollar, followed by a lack of faith in governmental attempts to stop that decline.