What is 0DTE GEX (zero-day gamma exposure)?

By Faizan Ahmad. Updated 2026-11-05.

0DTE GEX (zero-day gamma exposure) is the gamma exposure of options that expire today: how many dollars of stock dealers would have to buy or sell for each 1% move to stay hedged on same-day contracts. It needs its own measure because 0DTE positions are opened and closed within the session, so the once-a-day open interest count that ordinary GEX relies on mostly misses them. Tradytics builds 0DTE GEX from the day's trades on the live tape for SPY, SPX and QQQ, updates it every 30 seconds, and shows it four ways: by strike, as change over the last quarter hour to two hours, strike by strike through the day, and as key levels on the price.

Why does 0DTE gamma need its own number?

Two reasons: timing and size.

• Timing. Open interest is counted once a day, from the night before. A contract bought at 10 AM and sold at 2 PM never shows up in it. Same-day expiries have reached a majority of SPX options volume (a record 62.4% in August 2025, by Cboe's count), so an open-interest GEX leaves out much of the day's trading.
• Size. Gamma is how fast an option's delta changes as the price moves, and it gets very large for at-the-money options in their last hours. A strike right at the price on expiry day can flip from mostly worthless to mostly in the money on a small move, which is why same-day hedging clusters so tightly around the current price.

How is 0DTE GEX calculated on Tradytics?

From each same-day trade, as it prints:

1. Take the option's gamma at that moment.
2. Turn it into dollars per 1% move: gamma times 100 shares times the price times 1% of the price, times the contracts traded.
3. Assume the dealer took the other side. A customer buy leaves the dealer short gamma (negative); a customer sale leaves the dealer long gamma (positive).
4. Add it all up by strike, and keep the totals in 5-minute buckets so the day can be replayed.

The result is in dollars of stock per 1% move, built only from today's same-day trades. It is not the dealers' full inventory, and the bought or sold tag is inferred from where each trade printed against the bid and ask, as how to tell if options were bought or sold explains.

How is 0DTE GEX different from regular GEX?

The broader picture for every expiry is covered in how Tradytics models dealer positioning.

What are the four views of 0DTE GEX on Tradytics?

Switch between SPY, SPX and QQQ at the top of the card. The card remembers your symbol and view.

How do you read 0DTE GEX?

• Look at the price first. Same-day gamma matters most at the strikes nearest the price, which is why the 0.3% band is shaded.
• Sign tells you which way hedging leans. Positive gamma means dealer hedging trades against moves; negative means it trades with them. Positive vs negative gamma covers the mechanics.
• Change shows what is new. A strike that built most of its gamma in the last half hour is a fresh bet; one that built at the open may already be closing.
• Use it as a map, not a forecast. Tradytics studied 0DTE GEX over 396 sessions and found no pinning, magnet or direction effect. The one thing it showed was small and local: how much same-day gamma sat right at the price said a little about how choppy the next few minutes would be.

That matches outside research. Cboe estimated net market maker 0DTE hedging at no more than about 0.2% of SPX daily liquidity, and a 2025 study using actual market maker positions in S&P 500 index options found their gamma was usually positive, with a small average effect on volatility. More on the flow side in how to read 0DTE options flow.

Where do you see 0DTE GEX on Tradytics?

On the Options market page, in the Zero-day gamma exposure card, next to 0DTE flow for SPY, SPX and QQQ. It updates every 30 seconds from the live tape during the session. For gamma across every expiry, open a research options page such as SPY options.

Common questions

What does 0DTE GEX mean?

Gamma exposure for options with zero days to expiration: the dollars of stock dealers would trade per 1% move to stay hedged on contracts that expire today.

Why doesn't regular GEX capture 0DTE options?

Regular GEX usually starts from open interest, a count taken once a day. Same-day options are mostly opened and closed within the session, so they never appear in that count. 0DTE GEX is built from the day's trades instead.

Does 0DTE GEX pin the price to a strike?

Tradytics' study of 396 sessions found no pinning or magnet effect from 0DTE GEX, and no direction. Read it as where same-day hedging sits, not where the price will go.

Which tickers have 0DTE GEX on Tradytics?

SPY, SPX and QQQ, updated every 30 seconds through the session.

Is 0DTE GEX the same as 0DTE flow?

No. 0DTE flow shows the premium bought and sold in same-day options. 0DTE GEX turns those trades into the hedging they imply, by strike.

Sources

• Cboe: SPX 0DTE Options Jump to Record 62% Share in August (September 2, 2025): 0DTE at 62.4% of SPX volume.
• Cboe, 0DTEs Decoded: Positioning, Trends, and Market Impact (May 2, 2025): net market maker 0DTE hedging at most about 0.2% of SPX daily liquidity.
• Amaya, Garcia-Ares, Pearson and Vasquez, "0DTE Index Options and Market Volatility: How Large is Their Impact?" (January 2025, Cboe): market maker gamma usually positive, average effect reduces volatility about 0.2 points, maximum effect 3.3 points.
• Cboe, 0DTE trading resources: near-the-money options grow extremely sensitive to the underlying as expiration approaches.

• SPY options traded $763.86M in premium on 2026-11-04: $358.10M in calls and $405.76M in puts, a net bullish lean of $104.29M.
• Put/call ratio 1.13.
• Options price a move of about ±$6.67 by 2026-11-05.
• Max pain for 2026-11-04 is $755.0.

Updated 2026-11-05 07:45 UTC