I'm a bank. I gave a mortgage to a responsible homeowner who has bought a house that is within his means. Now that I've given this loan, a lot of my money is st

I'm a bank. I gave a mortgage to a responsible homeowner who has bought a house that is within his means. Now that I've given this loan, a lot of my money is stuck and I can't give loans to other people. However, I know it's a good loan with a very low risk of default. So I turn and say "Hey, I've given this loan, and here are the details which explain how much this loan is worth in non-real terms. You'll have to guess at the market interest rate to figure out the "real" (economic term) "value", but that's doable. Would you like to buy it from me?" If someone agrees to take possession of the loan, they'll have to reimburse the bank. Hey look! The bank has capital to repeat the process until it can't find any buyers of these loans. It's a good, honest bank, so it doesn't do anything fishy to move more loans. Eventually, we hit an equilibrium between people buying these loans, the bank holding loans, and people getting mortgages. Now you're telling me a derivative, the thing the bank sold, has no value? Sir, I'm going to have to disagree.