Record 62.4% of S&P 500 Options Volume Now Expires Same Day

SPX zero-days-to-expiration options reached a record 62.4% share of total SPX options volume in August 2026, averaging 2.4 million contracts daily, per Cboe. These same-day contracts force market makers to continuously buy or sell the underlying index to hedge — flows that can amplify moves in either direction. A basis point is 0.01 percentage point. No prior cycle matches this concentration.