What Are 0DTE Options, and Why Do They Behave Like Gambling?

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Same-day options explained: why theta and gamma peak on the last day, and the honest answer to trading them without it turning into a casino.

Last updated: 16 October 2026 · By Spencer Li, CFTe

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A 0DTE option is an option with zero days to expiry, which means it expires at the end of the same trading day you trade it. On the S&P 500 index there is now an expiry every trading day, since Cboe added Tuesday and Thursday expiries in 2022, and the same-day contracts have taken over. In July 2026, Cboe reported that 0DTE options made up a record 66.2% of all SPX options volume. An earlier Cboe note, for August 2025, put retail traders at an estimated 53% of that same-day volume.

They behave like gambling for a mechanical reason. With only hours left, there is almost no time value to cushion you. Theta takes whatever remains by the close, and gamma is at its peak, so the option swings from near-worthless to several times its price and back on small moves in the index. The payoff looks like a lottery ticket: usually a small loss, now and then a large win, and very little in between.

Do note that we do not teach options at Synapse Trading, and I do not trade them myself. My own trading is end-of-day swing trading in shares, forex and ETFs. This post sits under our ultimate guide to options trading, and it answers a question I keep seeing, almost word for word: “how do I trade 0DTE options without it turning into gambling?”

What exactly is a 0DTE option?

Any option on its last day is a 0DTE option. A monthly option bought 30 days ago becomes one on expiry morning. What changed in 2022 is that the most traded index options now have an expiry every single day, so a trader can open and close a fresh same-day position each session, all year.

Cboe announced the Tuesday and Thursday SPX expiries in April 2022, saying they would “expand the product suite to provide expirations every trading day of the week.” The volume followed. In September 2026 the same-day contracts set a monthly record of 3.4 million a day on SPX alone, according to Cboe’s own figures.

So why the rush? Part of it is price. A same-day option costs less than a monthly one at the same strike, because there is so little time left to pay for. Part of it is speed. You find out by the close whether you were right, which feels a lot like a game that pays out the same evening. Both of those are the same feature seen from 2 sides, and that feature is the problem.

What happens to theta and gamma on the last day?

Let me show you with a worked example, hypothetical and in round numbers.

An index trades at 100. A call at the 101 strike, expiring at today’s close, costs 0.40. With the VIX at 16, a rough rule says the market expects about a 1% move in a day, so about 1 point here (the VIX divided by 16 gives the expected daily range in percent).

For this call to break even at the close, the index has to finish above 101.40. That is a 1.4% rise in a few hours, bigger than the move the market expects on a normal day.

• The index closes at 100.90, up a respectable 0.9%. The call expires worthless. You lose 100% of the premium.
• The index closes at 102, a strong day. The call is worth 1.00. You make 150% on the premium.
• The index spikes to 101.50 at lunchtime and fades. For an hour the call was worth more than you paid, and by the close it is worth nothing.

That third line is the one that hurts. Gamma is so large on the last day that the option’s delta can swing from, say, 0.10 to 0.60 and back within a session, so the price lurches with every small move. Theta, meanwhile, is draining the time value hour by hour instead of day by day. You are not just betting on direction. You are betting on direction, size and timing, all inside one afternoon.

[INFOGRAPHIC: the same 101 call priced at 30 days and at 0 days, with the payoff line at the close and the 3 outcomes marked]

Why does that make 0DTE feel like a casino?

I have written before that trading is only gambling if you play like the gambler. The casino wins because it takes many small bets with the odds slightly in its favour, sized so that no single night can ruin it. The gambler loses because he does the opposite: big bets, chosen by feel, raised after a loss.

A same-day option pulls you towards the gambler’s side of the table. The bets are cheap, so it is easy to place a lot of them. Each one resolves fast, so the next one is always tempting. And the payoff is lopsided, so a single big win can paper over a long run of small losses, which is exactly how a slot machine keeps people at the stool.

You might think the fix is to sit on the other side and be the casino, selling the same-day options instead of buying them. It is a tempting idea. But the seller’s version has its own trap: many small wins, then one afternoon that takes back months, because the seller holds the lottery ticket’s tail.

The traders who have been through it say the same thing. One trader on r/options, 2 years into options, split his results by days to expiry in May 2026. His 0DTE trades lost at a 41% win rate while his longer-dated trades made money: “the data says 0DTE was just where my discipline broke.” In his case the leak was size. “i was sizing 0DTE 2-3x what i risked on longer-dated stuff,” he wrote. After cutting it: “the account isn’t bleeding for the first time in months.”

In his case the product was only half the problem. The other half was a size he picked, in his own words, “sizing emotionally because i could exit by close anyway.”

If you would rather start with the part of trading we do teach, the free 15-Minute Swing Trader’s Checklist covers the questions to ask before every trade, whatever you trade.

How do you trade 0DTE options without it turning into gambling?

The honest answer is that you can only make it less like gambling. The product’s shape stays the same whatever plan you bring to it. What a plan changes is whether one bad session can ruin you.

These are what I call the 3 lottery-ticket rules, and they are the rails I would hold anyone to before a single same-day trade.

1. The premium is the whole risk, and it fits your normal risk per trade. A bought option has no level to stop out at in the time available, so the premium you pay is the loss. If your rule is 1% of the account per trade, then on a SGD 50,000 account the premium is SGD 500 or less. No sizing up after a loss, ever. That is the moment the gambler takes over.
2. Only from a named place on the chart, decided before the session opens. The bottom of a range, a pullback in a clear trend, a failed breakout. If you cannot name the location before the market opens, there is no trade, only an itch.
3. Count them separately. Keep your same-day trades in their own column, the way the Reddit trader did, and judge them only after 100 to 200 of them. Fewer than that and you are looking at noise. If the column is losing while everything else is fine, the answer is in the data.

There is a fourth rule for anyone in Singapore, and it is practical rather than mathematical. The US market opens at 9.30 pm or 10.30 pm Singapore time, depending on the season, and closes at 4 am or 5 am. A same-day option expires at that close. If you have a day job, you are either asleep when your trade resolves, or awake at 4 am and paying for it the next day.

[INFOGRAPHIC: the 3 lottery-ticket rules as a pre-trade checklist, with the Singapore clock beside it]

So which side of the table are you on when you open the options app late at night? Are you placing the bet the plan allowed, or the one that feels exciting?

FAQ

What does 0DTE mean?
0DTE means zero days to expiry. A 0DTE option expires at the end of the same trading day it is traded, so all of its remaining time value disappears within hours.

Are 0DTE options gambling?
They behave like gambling because the payoff is lopsided: usually a small loss, now and then a large win. Whether your trading is gambling depends on your size and your process, and a same-day option makes both harder to keep under control.

Why do 0DTE options lose value so fast?
Because there is almost no time left for the move to happen. Theta drains what remains of the time value by the close, and gamma is at its peak, so the price swings hard on small moves in the underlying.

Is selling 0DTE options safer than buying them?
Selling wins more often, but each loss can be many times the premium collected. The seller trades frequent small gains for rare large losses, so the risk moves rather than goes away.

Can you trade 0DTE options from Singapore?
Yes, through a broker that offers US-listed options, once it has approved your account for options. The US session runs from 9.30 pm or 10.30 pm to 4 am or 5 am Singapore time, so same-day options expire in the middle of the Singapore night. Our guide to choosing an options broker from Singapore covers the approval and cost checks.

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About the author. Spencer Li is the founder of Synapse Trading and a Certified Financial Technician (CFTe) with 15 years of trading across stocks, forex, crypto, commodities, and bonds. His trade log is public: every trade since April 2024, dated, losses left in. He teaches low-risk swing trading in 15 minutes a day, one system for any market.

Educational content only, not personalised financial advice. Trading carries risk, including loss of capital, and isn’t suitable for everyone. Past performance is not indicative of future results. Synapse Trading is not licensed or regulated by MAS.

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Educational content only, not personalised financial advice. Trading carries risk, including loss of capital. Past performance is not indicative of future results. Synapse Trading is not licensed or regulated by MAS.