What exactly are 0DTE options, and how are they different from regular options?

Simply put, 0DTE (Zero Days to Expiration) means 'same-day expiry options'—the option contract you buy or sell on a trading day expires that very day. It's not a separate type of option, but a general term for any contract (whether issued six months ago or last week) that reaches its expiration day.^[1] In other words, 0DTE isn't a newly invented financial instrument; it's the final stage in the life cycle of every option contract. Just as everyone experiences their own 'last day,' every option contract has its expiration day, and 0DTE refers to that 'last day' itself.

For example: if you buy a call option that expires in a month and hold it until the expiration day, it becomes 0DTE; but you could also buy a contract today that expires today, and it's 0DTE from the start. The difference is that regular options have a longer period for the price to 'gradually change,' while 0DTE has only a few hours, with time value nearly zero, and price movements are entirely driven by the underlying's immediate fluctuations. You can think of regular options as a TV series with many episodes left, while 0DTE is the final episode before the series finale—all the plot must unfold within a few hours, so every minute is full of uncertainty.

Why are 0DTE options so cheap? Are they worth buying?

0DTE options are cheap because their time value is nearly zero—on the expiration day, Theta (time decay) accelerates sharply, especially in the afternoon, with prices draining away like sand in an hourglass.^[8] So a 0DTE call option might cost only a few dozen dollars, while the same strike with a month to expiry could cost several hundred. It's like buying a movie ticket for tonight versus one for a month from now—the prices differ because tonight's ticket gives you only a few hours to watch, while the month-ahead ticket gives you a month to plan.

But 'cheap' doesn't mean 'low risk.' Gamma for 0DTE options amplifies dramatically at expiration, so small moves in the underlying can cause extreme swings in option profits and losses—you might double your money in minutes, or lose 90% in minutes.^[3] It's like walking a tightrope: when it's calm, you're steady, but a small gust of wind can send you tumbling. So, it suits short-term traders with a clear view of the day's direction, but it's definitely not a long-term investment tool. If you're just looking to gamble, be prepared to lose everything.

Why are 0DTE options so popular with retail investors, and how big is the trading volume?

The appeal of 0DTE to retail investors lies in the low premium, allowing them to bet on short-term moves at a lower cost, and they don't have to worry about overnight gap risk.^[8] You can buy at the open and close the position before the close, settling everything that day, without the anxiety of holding overnight. It's like riding a log flume at an amusement park—you might get wet, but it's over when it's over, and you don't have to worry about nightmares at night.

How big is the trading volume? According to Cboe, in 2025, SPX 0DTE options averaged about 2.3 million contracts per day, accounting for 59% of total SPX options volume; 0DTE contracts made up 24.1% of all listed options volume in the U.S., up from 21.5% in 2024.^[4] It's safe to say that 0DTE has become one of the most active 'players' in the U.S. options market. It's like a restaurant where each dish is cheap, but with many customers, the revenue naturally goes up.

What are the differences in settlement between SPX and SPY 0DTE options?

SPX (S&P 500 index options) are cash-settled and European-style, with a contract multiplier of $100 per point, settling directly in cash at expiration, with no stock assignment risk.^[5] Moreover, SPX 0DTE contracts (SPXW) use PM settlement—settling at the closing price on the expiration day, and you can trade until the close.^[6] This means if you hold SPX 0DTE options, the system automatically calculates the difference and credits your account, without any stock delivery, so you don't have to worry about suddenly receiving a pile of stocks.

ETF options like SPY and QQQ involve physical delivery: if your option is in-the-money at expiration, you'll be assigned or deliver the corresponding ETF shares, with settlement occurring T+1 trading day.^[7] This means if you hold an in-the-money 0DTE SPY option without closing it, you might unexpectedly receive a bunch of shares after the close, taking on overnight risk. It's like buying a lottery ticket and winning, but instead of cash, you get a pile of prizes that you have to deal with yourself, possibly incurring storage and transport costs.

Does opening and closing a 0DTE option on the same day count as a day trade?

Yes. As long as you open and close the same 0DTE option on the same day, whether you buy first then sell or sell first then buy, it counts as one 'day trade' under applicable rules.^[11] However, note that the original 'Pattern Day Trader' (PDT) rule in the U.S. has undergone major changes: the SEC has approved amendments to FINRA Rule 4210, eliminating the PDT label and the $25,000 minimum account equity requirement, with the new rule effective June 4, 2026 (currently in effect). Now, margin requirements are based on the actual risk exposure taken that day, rather than the old threshold of '4 day trades within 5 trading days.'

So, even if you frequently trade 0DTE options intraday, you no longer need to follow the old '5-day, 4-trade, $25,000' PDT rule—that's been abolished. But your account will still have margin requirements based on actual risk exposure, so it's best to confirm the current rules with your broker before trading to avoid restrictions or forced liquidation due to insufficient margin.

How risky are 0DTE options? Can they lose everything in an instant?

The risk is very high, especially for sellers. If you sell naked (uncovered) call options, and the underlying price surges, the potential loss is theoretically unlimited.^[9] It's like selling an 'unlimited liability' insurance policy—if a claim occurs, you could lose everything. Even as a buyer, your maximum loss is limited to the premium, but Gamma for 0DTE is extremely high, and the price can go to zero within minutes. It's like playing a claw machine at an arcade—you might lose only the coins you put in, but most of the time you get nothing—your capital is limited, but it's likely to be wasted.

Additionally, if your broker force-liquidates your 0DTE positions before the close, it may execute at unfavorable prices, limiting profits or even causing losses.^[10] It's like being at an auction, hoping for a better price, but the auctioneer suddenly announces 'last three minutes,' forcing you to bid hastily, possibly overpaying or underselling. So, 0DTE is not a 'low-cost, low-risk' game, but a 'low-cost, high-volatility' gamble.

Can 0DTE options amplify intraday market swings?

This is the biggest concern for regulators and institutions. JPMorgan strategist Marko Kolanovic warned that in extreme scenarios, hedging by 0DTE market makers could amplify a 5% intraday decline in the S&P 500 within 5 minutes into a rout of up to 25%—potentially triggering a chain reaction similar to the 1987 'Black Monday.'^[12] It's like dominoes: once the first falls, the rest follow in sequence, accelerating and potentially causing a market-wide cascade.

The reason is that 0DTE volume is massive, and market makers, to hedge Gamma risk, sell futures or ETFs when the market drops, further pushing prices down, creating a 'decline-hedge-decline' spiral. It's like in a crowded theater, someone shouts 'fire,' and everyone rushes to the exits, only to block them, causing more chaos. So, 0DTE isn't just a personal gamble; it can also affect the stability of the entire market.