Citadel Securities reports $9.6T in US options expiring September 18

Nearly $9.6 trillion in US stock options notional is set to expire by September 18, 2026, representing roughly 35% of the entire US options market. Of that total, $6.2 trillion is concentrated on September 18 alone, a single-day figure that would shatter the previous record of $7.7 trillion set just three months ago in June 2026. The numbers come from Citadel Securities’ Global Market Intelligence report, published August 31 by the firm’s Scott Rubner. What’s actually expiring, and why it matters The $9.6 trillion figure represents about 35% of aggregate US options exposure, based on open-interest data sourced from Bloomberg as of August 27, 2026. The September 18 expiration date alone accounts for roughly 23% of total exposure. Rubner’s report notes that this event is on pace to exceed the prior record. In June 2026, an $8.3 trillion options expiration event shifted timing due to the Juneteenth holiday, ultimately producing a $7.7 trillion single-day expiration. The timing couldn’t be worse (or more interesting) When dealers hold long-gamma positions, as they reportedly do now, they act as natural dampeners on volatility, buying dips and selling rallies. Once those positions expir...