banks are heavily regulated and cannot just put deposits (the money you put into a bank constitute a loan to the bank) into stocks. They have to invest more con

banks are heavily regulated and cannot just put deposits (the money you put into a bank constitute a loan to the bank) into stocks. They have to invest more conservatively, e.g give money to solid companies or hold low risk bonds. See Basel-rules to learn more about risk weighted assets (RWA): https://en.wikipedia.org/wiki/Basel_III https://en.wikipedia.org/wiki/Basel_III