How were the stock market crash and the collapse of the banking system related

Many banks had invested in the market and faced significant shortfall; several faced insolvency. The Crash also prompted a run on gold deposits, further reducing the amount of deposits banks had on hand. As a result, banks curtailed their lending activities, contributing to an economic slowdown.

They are related because when the stock market crashed due the the exponentially increasing stock prices and the bubble it created instead of the federal reserve flooding the us in money, like it should have, they cut off the money supply creating a worse depression