Speaking of gamma, there was chatter on some desks a hedge fund got stopped out of a huuuge short gamma trade and had to liquidate a couple hundred billion in positions. Not the reason for the selloff but maybe exacerbated the depth.
This whole market has been built on illusionary liquidity and the subsequent private equity bids that have legitimized these valuations. Selling premiums, exploiting the carry trade works until it doesn't. The global economy is in serious trouble if the group think that got us here decides to reverse itself.