One day remaining
1DTE options have one day remaining until expiration. Using calendar days, a Thursday position in a Friday-expiring contract is 1DTE. “Expires next trading session” is not always the same thing: Friday to Monday spans three calendar days. See how DTE is counted.
A trader may close the position while it still has 1DTE, carry it into the 0DTE session, or hold it to expiration. Each choice has different exposure. The same call, put or spread construction can be used; the label alone does not define a trading strategy.
Overnight exposure and gaps
A position held overnight remains exposed to earnings, economic news and other events. The underlying can reopen beyond a strike or a planned exit level. The option market may be closed when news arrives, and the next executable quote may be far from the previous close.
One extra day does not ensure an orderly exit or enough time for a forecast to work. Time passes while the market is closed, but observed option prices also incorporate anticipated events and changing volatility. Do not estimate the next opening price by simply subtracting one quoted theta value.
A hypothetical overnight vertical spread
Consider a 100/102 bull call spread bought for a $0.70 net debit with a 100-share multiplier and matching expirations. Its theoretical maximum expiration loss is $70 and maximum profit is $130 before costs. At 101, its expiration value is $100, leaving $30 profit. At 100 or lower, it loses the debit.
These numbers illustrate the bull call spread; they are not a recommended trade. An overnight gap can move the spread directly from one part of its payoff range to another. Share delivery, unmatched exercise and early assignment can create obligations outside the simplified expiration graph. The existing calculator explores the payoff assumptions.
When 1DTE becomes 0DTE
Recheck the last trading time, position size and broker deadlines before the final session. A remaining long leg will not necessarily be exercised to offset an assigned short leg. Monitor every leg and the resulting account position.
Read 0DTE Options for the final-day behavior and 0DTE & 1DTE Risks for the full expiration checklist.
Sources and further reading
Reviewed 18 September 2026. Contract availability and terms can change; verify the selected series with the exchange and broker. Examples are hypothetical and exclude trading costs. Editorial standards.