What are 0DTE options?
0DTE options, short for zero days to expiration, are option contracts traded on the day they expire. Any option becomes a 0DTE option on its last day, but the term usually refers to index and ETF options such as SPX, SPY and QQQ, which now list an expiration every trading day. Because they have only hours of life left, their prices respond to small moves in the underlying far more violently than longer-dated options.
Why every day is now an expiration day
For decades, options expired monthly, on the third Friday. Weekly expirations were added later, first on Fridays and then on other days. Over time, exchanges added more expiry days for the most liquid index products until SPX had an expiration every weekday. SPY and QQQ followed with daily expirations.
The result is that on any given trading day, there is always a set of index options expiring that afternoon. Single-stock options are different: most individual stocks list weekly and monthly expirations only, so a single stock's options are 0DTE only on those expiry days.
Same-day contracts now account for a large share of daily SPX options volume, which is why they have become a central part of how the index trades intraday.
How they are priced
A 0DTE option's value is almost entirely about one question: where will the underlying be at the close? There is no time for a long trend, so the option is priced off the range the market expects for the rest of the session. That range shrinks every minute.
That makes the Greeks extreme. Gamma near the money is very large, because a small move can take an option from worthless to meaningfully in the money. Theta is also large relative to price, because the remaining time value has to reach zero by the close. A 0DTE at-the-money option can lose a large fraction of its value over a quiet hour.
Implied volatility on 0DTE contracts can look unusual too. With so little time remaining, a small difference in price translates into a large difference in implied volatility, and the figures jump around during the day. Many traders find it more practical to think in terms of the dollar move priced into the at-the-money straddle.
How they settle
Daily SPX contracts are PM-settled and cash-settled: at the close, in-the-money options pay the difference between the closing index value and the strike, times 100. There is no stock delivery, so no assignment risk after the close.
SPY and QQQ 0DTE options are physically settled. An in-the-money option at the close is exercised automatically, delivering or taking 100 shares per contract. A trader short an SPY 0DTE option that finishes near the strike faces pin risk: uncertainty about assignment and exposure to after-hours moves. Traders who do not want a share position close or roll their contracts before the bell.
The settlement difference also changes how traders manage the final minutes. With SPX, a position that finishes in the money simply pays cash, and there is nothing to manage after the bell. With SPY and QQQ, a position held through the close becomes a share position overnight, which brings margin and gap risk that the options trade was never meant to carry.
What 0DTE options do to the market
Because 0DTE gamma is so concentrated, hedging those positions can have an outsized effect on intraday price relative to the premium involved. When dealers are long that gamma near the price, their hedging leans against moves; when they are short it, their hedging leans with them, and afternoon moves can extend further than the morning suggested.
The positioning also changes quickly. Much 0DTE volume is opened and closed within the same session and never appears in open interest, so maps built on overnight open interest miss part of the picture. Intraday tools try to estimate it from the live tape.
And it disappears daily. Whatever structure the same-day contracts create is gone by the close, and a new set takes its place the next morning.
The risks
A 0DTE option can go to zero within hours. The same convexity that turns a small favourable move into a multiple of the premium turns a small adverse move, or simply a quiet afternoon, into a total loss. For sellers, the risk is reversed: small, frequent gains punctuated by occasional losses many times larger.
Liquidity can also change sharply into the close, especially for strikes far from the money, and spreads can widen. Sizing for the worst case rather than for the typical day is the discipline most often cited by people who trade these contracts regularly.
Behavioural risk is part of the picture too. Because 0DTE contracts are cheap and resolve within hours, it is easy to trade them often and in size. Many traders who use them set rules in advance, such as a maximum premium per day, precisely because the product makes it easy to stack many small decisions into one large loss.
Common questions
What does 0DTE stand for?
Zero days to expiration: the option expires at the end of the current trading day.
Which options have 0DTE every day?
SPX, SPY and QQQ list expirations every trading day. Most single stocks only have weekly and monthly expirations.
Can you get assigned on 0DTE options?
On physically settled products such as SPY and QQQ, yes, if a short option finishes in the money. SPX 0DTE options settle in cash, so there is no share delivery.
0DTE options are contracts on their final day, listed daily for SPX, SPY and QQQ. Their gamma and theta are extreme, SPX versions settle in cash while SPY and QQQ deliver shares, and they can go to zero within hours.
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