0DTE options and same-day market structure

What makes 0DTE different

An option expiring today has very little time value left, so its delta reacts violently to small moves in the underlying. That produces unusually high gamma near the money and unusually fast changes in required hedges.

Because the exposure is created and extinguished within one session, its influence is concentrated rather than spread across days.

How same-day structure evolves through the session

Early in the session, positioning is still forming and structure is provisional. Through the middle of the day, exposure around the most active strikes tends to anchor price. Into the final hours, decay and unwinding can either pin price near a heavily traded strike or release it once exposure has drained.

• Pinning behaviour is most common when exposure is concentrated and price sits near it.
• Release behaviour is most common once the anchoring strikes lose relevance.
• Same-day structure should be re-read intraday, not set once at the open.

Risk considerations

0DTE instruments carry rapid, non-linear loss profiles. Using same-day structure to understand the environment is a different activity from trading same-day options, and the two should not be conflated. Define risk and invalidation before acting on any structural read.