What "0DTE" means
DTE stands for days to expiration. A 0DTE option has zero days left: it expires at the end of the session you trade it in.
Any option becomes a 0DTE option on its final day. What changed is supply. SPX now lists an expiration for every trading day of the week, so there is always a contract expiring today.
Why there's an SPX expiry every day
Cboe filled out the week in 2022. SPX Weeklys already expired on Monday, Wednesday and Friday. In April 2022 Cboe announced Tuesday expirations starting April 18, 2022 and Thursday expirations starting May 11, 2022, to "provide expirations every trading day of the week" (>Cboe).
Once every day had an expiry, same-day trading became a daily habit instead of a Friday event.
How fast the share has grown
Cboe publishes the 0DTE share of SPX volume in its monthly notes. Here is the run of records.
| Month | 0DTE share of SPX volume | Other detail | Source |
|---|---|---|---|
| Feb 2025 | 56% (record) | SPX ADV record 3.49M contracts | >Cboe |
| May 2025 | Over 61% (record) | Retail 54% of SPX 0DTE volume | >Cboe |
| Aug 2025 | 62.4% (record) | ~2.4M 0DTE contracts a day, retail ~53% | >Cboe |
| Sep 2025 | 60% | SPX ADV record 4.26M contracts | >Cboe |
| May 2026 | 65% | From Cboe's Q2 2026 earnings slides | >Investing.com |
A little arithmetic puts the share in contracts. In September 2025, 60% of 4.26 million is about 2.56 million same-day SPX contracts a day. In August 2025, 2.4 million contracts at a 62.4% share implies total SPX volume of roughly 2.4 ÷ 0.624 ≈ 3.85 million a day.
The trend continued into 2026. Cboe's Q2 2026 industry review says 0DTE volume across options was up 46.2% year to date, to more than 20 million contracts a day, and that "SPX 0DTE volume has nearly tripled since the start of 2024" (>Cboe).
Who trades 0DTE, and how
Retail is the largest group. Cboe's research puts retail at roughly 50% to 60% of SPX 0DTE trading (>Cboe).
Access matters too. Cboe tied the February 2025 record partly to "expanded access, with Robinhood rolling out index options trading to all its customers in late Jan" (>Cboe).
Most of the flow has capped risk. According to the same Cboe study, "over 95% of all 0DTE trades are done in a limited risk format," meaning long options outright or short options inside spreads. Only 4% of SPX 0DTE trading is in naked short options (>Cboe).
Why same-day options behave differently
Two Greeks dominate on expiration day.
- Gamma measures how fast an option's delta changes as price moves. SpotGamma notes that gamma "spikes for at-the-money strikes" as expiration approaches, so hedging flows intensify through the afternoon (>SpotGamma).
- Theta is time decay. With hours left, an option's time value melts fast. SpotGamma describes 2:00 to 3:30 PM ET as the window when "gamma is at its peak" and "theta is at its most punishing" (>SpotGamma).
In plain terms: a small move in the index can swing a 0DTE option's value a long way, in either direction, in minutes.
| 0DTE option | 30-day option | |
|---|---|---|
| Time value at the open | Small, and gone by the close | Larger, decays over weeks |
| Sensitivity to a small index move | Very high near the strike | Lower |
| Time to be right | Hours | Weeks |
| Common use | Intraday views, premium selling in spreads | Swing views, hedges |
The risks worth naming
- All-or-nothing expiry. A long 0DTE option that finishes out of the money expires worthless the same day.
- Fast losses on short premium. Selling same-day options collects small credits that a sharp move can wipe out. This is why spreads with a bought wing are the norm.
- Cost drag. Commissions and bid/ask spreads are a bigger share of a small premium.
- Crowded timing. When gamma peaks late in the day, moves near big strikes can be sharp.
How to use it on the Loomi.Ai Desk
The Loomi.Ai Desk gives you the context around same-day trading. It does not give you 0DTE trade calls.
- Options flow scanner. It shows "unusually large or active options trades, including trade size and how the orders reached the market." Loomi's own caveat: "a large trade alone does not reveal the buyer's full position."
- Dealer gamma (GEX). The GEX map estimates options-dealer positioning and highlights reference levels, including call and put walls, to compare with price. Our GEX explainer covers the basics.
- GEX Regime and Dealer's Hand. The /gex-regime/ page shows net dealer gamma live and warns as price nears a wall. It includes a planned 0DTE credit-spread ladder of defined-risk verticals. Loomi says plainly that "the ranked 0DTE ladder and the streak pause are in build and are not live yet."
The Desk costs $8/mo intro, then $20/mo. Options flow, GEX and dark pool data are included.
Put the research to work on your Desk
Explore the tools behind the research, compare the available access, or open your Desk if you already have an account.
FAQ
What does 0DTE mean in options? Zero days to expiration. The option expires at the end of the same trading session.
What percentage of SPX volume is 0DTE? Cboe reported a record 62.4% in August 2025. Investing.com's summary of Cboe's Q2 2026 slides puts it at 65% as of May 2026.
Why did 0DTE trading grow so fast? SPX gained an expiry every weekday in 2022, and access widened. Cboe cited Robinhood's rollout of index options to all customers in late January 2025.
Are 0DTE options mostly naked bets? No. Cboe found over 95% of 0DTE trades are limited-risk, and only 4% of SPX 0DTE volume is naked short options.
Loomi.Ai provides educational market research, not financial advice. Options involve substantial risk, and 0DTE options can lose their full value in a single session.
Sources
- >SPX 0DTE Options Jump to Record 62% Share in August, Cboe
- >SPX 0DTE Options Jumped to Record 56% Share in Feb, Cboe
- >SPX 0DTE Options Jump to 61% Share on Retail Resurgence, Cboe
- >SPX Options Jump to Record 74% Market Share, Cboe
- >0DTEs Decoded: Positioning, Trends and Market Impact, Cboe
- >State of the Options Industry: Q2 2026, Cboe
- >Cboe to Add Tuesday and Thursday Expirations for SPX Weeklys Options, Cboe
- >Cboe Q2 2026 slides: 0DTE options surge to 65% of SPX, Investing.com
- >0DTE Options: The Complete Guide, SpotGamma