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Expiration risk5 minute read
0DTE gamma and expiration risk
Understand why same-day options can change sensitivity quickly and why closing time is not the end of the risk
由 Mark 撰寫 · 官方資料列於文末
直接解答
A 0DTE option expires that trading day. Near the strike, a small underlying move can change delta quickly, which is the local sensitivity described by gamma. Time value is also short-lived, and an open short or near-the-money position can face exercise, assignment, or resulting stock exposure after the option market closes. These mechanics make same-day options different from simply shorter versions of longer-dated contracts
Gamma changes the delta snapshot
Delta is an all-else-equal local estimate, not a fixed share equivalent for the whole day. Near expiration and near the strike, gamma can make delta change rapidly after a small stock move, so a payoff expectation based on one snapshot can become stale
The deadline compresses decisions
There is little time for a thesis to develop or for a wide market to normalize. Bid-ask spreads, liquidity, and the remaining premium can matter as much as the direction of the underlying when a position must be adjusted
Expiration requires an operational plan
Review settlement style, broker cutoffs, automatic-exercise thresholds, buying power, and the risk of after-hours moves. Closing before expiration can reduce uncertainty only after the closing order actually fills
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