How did many banks fail consumers in the stock market crash of 1929?

When the stock market crashed, businesses lost their money. Consumers also lost their money because many banks had invested their money without their permission or knowledge. The mortgages were small relative to property prices and losses suffered by banks on their mortgages were insignificant. Rather, banks failed because mortgage lending rendered banks inherently illiquid and unable to withstand the mass withdrawal of deposits during the depression.

When the stock market crashed, businesses lost their money. Consumers also lost their money because many banks had invested their money without their permission or knowledge