Cboe 0DTE S&P 500 Options & SEC Leveraged ETF Rules: Are Retail Gamma Flows Suppressing VIX or Priming a Volatility Shock?

Zero-days-to-expiration (0DTE) contracts on Cboe Global Markets now exceed 50% of daily S&P 500 (SPX) options volume, interacting with 2x single-stock leveraged ETFs governed by SEC Rule 18f-4's 200% Value-at-Risk (VaR) limit to reshape intraday dealer gamma hedging and closing rebalancing flows.

Cleared through the Options Clearing Corporation (OCC) and supervised under FINRA margin rules, retail and institutional 0DTE flows routed by brokerages like Robinhood Markets (NASDAQ: HOOD) onto Cboe Global Markets (CBOE: CBOE) require continuous delta-hedging by wholesale market makers such as Citadel Securities. Balanced call and put overwriting often pins the S&P 500 and dampens traditional 30-day VIX readings.

However, under U.S. Securities and Exchange Commission (SEC) Rule 18f-4, 2x leveraged single-stock ETFs issued by Direxion and GraniteShares must mechanically rebalance total-return swaps in the same direction as underlying price moves at the 4:00 p.m. ET close. Do systematic 0DTE options flows stabilize intraday equity liquidity, or do leveraged ETF rebalancing mechanics amplify tail-risk selloffs?