Excellent article! One question though.

I fail to see how derivative trading is rent-seeking. You say it is because it adds no value to society. If that were the most important criterion, then postage-stamp trading would also be a rentier’s occupation. When evaluating whether something is a rent, I like to look at its externalities. Does it impose external costs on third parties, or on society as a whole?

Derivatives can be equivalent to an insurance policy. Or they can provide a cheap form of leverage — in other words, you no longer need to pay that rent-seeking bank.