Hello! The major cause of the stock market crash was that before it began, people were borrowing money and not able to pay it back. The 1920's was a time where new technologies like cars and phone were being made. People started borrowing money to buy these nice gadgets. They were so soaked in into all of that, they didn't even think much about paying any money back. Before the stock market crash, brokers started to sell their loans and people started getting their money out of banks before they closed.
