It's a simple question prescribed in the title. The basis that I ask this is because banks have two fundamental functions. They can act as a warehouse for you to put your money in it. (They would also provide services such as records, ATMs, etc.) The second is to act as an investment corporation in the form of checking accounts. The question then proposed is whether the banks should be able to have access into their warehouse of money in order to fund their investment operations. You can look at the Glass-Steagle Act, which is legislation explicitly to deal with such issue.