https://www.lrb.co.uk/the-paper/v46/n17/john-lanchester/for-every-winner-a-loser

“… total value of all the economic activity in the world is estimated at $105 trillion … value of the financial derivatives which arise from this activity … $667 trillion. … in terms of the things it produces, that business is useless. It does nothing and adds no value. It is just one speculator betting against another…”