In 1929 the stock market crashed because what?

Investors large and small were buying on margin, meaning they were buying on credit that they couldn't pay. At the time there were no controls on investing practices . After the crash the government stepped in with rules and regulations to prevent another meltdown. Under Reagan and both Bush Presidencies those regulations were relaxed to almost nonexistent as before the Great Depression. That is why we nearly had a larger crash.Some people may misdirect this with irrelevant facts and finger pointing but that is essentially what happened.