Black Monday is the name commonly given to the global, sudden, severe, and largely unexpected stock market crash on Monday, October 19, 1987. In Australia and New Zealand, the day is also referred to as Black Tuesday because of the time zone difference from other English-speaking countries. All of the twenty-three major world markets experienced a sharp decline in October 1987. When measured in United States dollars, eight markets declined by 20 to 29%, three by 30 to 39%, and three by more than 40%. The least affected was Austria while the most affected was Hong Kong with a drop of 45.8%. Out of twenty-three major industrial countries, nineteen had a decline greater than 20%. Worldwide losses were estimated at US$1.71 trillion. The severity of the crash sparked fears of extended economic instability or even a reprise of the Great Depression.