You still think SP500 not driven by increasing margin? See below

. Keyword: options, intraday.
https://www.bloomberg.com/news/arti...-tougher-margin-rule-as-zero-day-options-boom
Wall Street Faces Tougher Margin Rule as Zero-Day Options Boom
The world’s largest derivatives-clearing house is seeking to introduce fresh margin requirements on Wall Street firms as the frenzy in zero-day options shows no sign of letting up. Options Clearing Corp. is looking to harden rules on
intraday margins at brokers and dealers in the event their risk exposures breach certain thresholds, according to a spokesperson. OCC is also proposing a monthly add-on to their collateral contributions to ensure the smooth functioning of markets, among other obligations, the person said. It’s the latest push from industry supervisors to secure market discipline amid the trading frenzy in equity contracts that expire within 24 hours
https://www.bloomberg.com/news/arti...-tougher-margin-rule-as-zero-day-options-boom