What was the immediate cause of the Stock Market Crash of 1929?

What caused stocks to suddenly start to decrease in value? Basically, why 1929 as oppose to 1927 or 1925?





I am not looking for "buying on margin" or speculation, but rather an immediate cause--what set off that chain of dominoes?|||Greedy bankers and financial institutions.|||After World War I, France, which had been the bread basket for western Europe was ravaged (having all the farms between Paris and the German border does that). So during the period after WWI the US had been a major producer and seller of foodstuffs to Europe, but in 1929, France yielded a bumper crop.


This lowered the value of wheat on the market and caused massive problems for farmers. People who had invested in the wheat trade lost vast amounts of money and this was the first proverbial domino to fall.