0DTE options flow: why same-day expiry signals work differently

Why 0DTE changed everything

The CBOE's introduction of daily SPX expirations in 2022 created a new class of options, ones that expire the same day they're traded. By 2024, 0DTE options accounted for more than half of SPX notional volume on most trading days. The mechanics of 0DTE are fundamentally different from anything that existed before, and the flow signals they generate need a separate framework.

The core difference: in multi-day options, premium is partly a bet on direction and partly payment for time. In 0DTE options, there is essentially no time value. What you're paying for is pure gamma, the right to participate in today's move. That changes who buys them, why they buy them, and what their purchases signal.

The four 0DTE player types

Understanding 0DTE flow starts with knowing who's on the other side of each print.

Retail momentum traders. The largest category by count, not by size. They're buying OTM 0DTE calls when SPY is trending up and OTM puts when it's breaking down. This activity is largely reactive and noise. High volume at multiple strikes from small orders is the signature.

Market makers and structured products desks. Dealers who sold long-dated SPX variance swaps or structured products need to dynamically delta-hedge their book daily. Their 0DTE activity is mechanical, not directional, it reflects the shape of their existing book, not a view on today's move. Very large orders near ATM strikes often fall in this category.

Institutional intraday hedgers. Portfolio managers hedging event risk for a single day, a CPI print, an FOMC decision, an earnings after close. They buy 0DTE puts or calls not as directional bets but as binary protection. These are credible signals because they represent real premium at risk.

Event-driven and stat-arb desks. Quantitative traders arbitraging the implied move vs expected realized vol, or positioning around known gamma concentrations. They often cluster around specific strikes (gamma walls) and trade both sides. Their activity can create self-fulfilling price magnets.

0DTE flow vs multi-day flow: the key differences

The gamma wall effect

One phenomenon unique to 0DTE (and near-term expiry) is the gamma wall, a strike where open interest is so concentrated that market makers must dynamically hedge so aggressively they create a self-fulfilling price magnet.

When dealers are short gamma at a particular strike, they must buy as price approaches from below and sell as it approaches from above. This creates a feedback loop that pins prices to gamma-heavy strikes, especially in the afternoon when 0DTE gamma is at its peak sensitivity.

Watching where 0DTE OI builds up at the open can tell you where price is likely to be pulled toward in the afternoon. A 5200 strike with 50,000 contracts of 0DTE OI in SPX is a gravitational field, not a guarantee, but a force that traders position around.

Time-of-day patterns in 0DTE flow

9:30–10:00 (Opening flow). The highest premium, highest volume window. Institutions establishing intraday hedges, directional bets on overnight developments, and reactive trades to pre-market news. This is the most informative 0DTE window, but also the most crowded. Large sweeps at the open that are not just reacting to a gap often signal real intraday conviction.

10:00–11:30 (Settling period). The initial directional impulse either extends or fades. 0DTE OI builds as traders add to opening winners or establish new positions. Watch for clusters forming around specific strikes, that's where gamma walls are developing.

11:30–13:30 (Mid-day noise period). Volume drops. Retail dominance increases. Most 0DTE prints in this window are noise, low-premium, reactive, retail-driven. Filter these out unless premium is unusually large.

13:30–14:30 (Institutional accumulation window). Larger players often use this window to establish afternoon positions. Unusual flow here, especially large sweeps, has above-average predictive value for the close. This is also when gamma exposure peaks for ATM strikes.

14:30–15:30 (End-of-day positioning). Delta hedging peaks, volatility typically compresses toward the close (unless a catalyst exists). Lots of closing trades mixed in. Interpret flow cautiously, much of it is unwinding, not new positioning.

15:30–16:00 (Closing rush). Mostly unwinding and gamma hedging. Almost entirely noise from a directional signal standpoint.

When 0DTE flow is credible

Not all 0DTE flow should be filtered out. These characteristics make a 0DTE print worth paying attention to:

Large premium, not large volume. $500K of 0DTE calls at one strike tells you something. 10,000 contracts at $0.02 tells you nothing. Premium is the signal; contract count is noise for 0DTE.

Specific OTM strikes, not ATM. ATM 0DTE buying is mechanical or momentum-chasing. OTM 0DTE buying that's large premium on a sweep is a specific bet on a specific move. That's more interesting, someone is paying for a defined outcome.

Cross-asset confirmation. 0DTE flow that aligns with rising IV, unusual dark pool activity, or sector-level flow in the same direction carries more weight than flow in isolation.

Events with known timing. Large 0DTE put buying before a CPI print at 8:30am, that's a hedge. Large 0DTE call buying before an earnings release after the close on a day with weekly expiration, that's event positioning. Both are credible even though 0DTE is involved.

Repeat sweeps across multiple times. If the same OTM strike gets swept repeatedly throughout the day, someone is building a position deliberately. That's different from a one-time reactive buy.

When to filter out 0DTE flow

ATM calls or puts after a gap in the same direction. The stock gapped up, and now there's 0DTE call buying. That's retail chasing, not institutional positioning. Wait for price to consolidate before treating momentum flow as signal.

High volume but low per-contract premium. Thousands of contracts at $0.01–$0.05 is lottery-ticket retail. Institutions don't trade that way.

Flow that reverses direction mid-session. If the same ticker shows 0DTE call buying at open and then 0DTE put buying at noon, that's noise, people unwinding, not building conviction.

Anything in the 11:30–13:30 window without extraordinary premium. Low-volume mid-day 0DTE is almost always noise. Set a higher premium bar during this window or filter it entirely.

0DTE flow on individual stocks vs indices

Most 0DTE volume is concentrated in index products, SPX, SPY, QQQ, NDX. Individual stock 0DTE is less common and often higher-signal because fewer participants trade it.

Single-stock 0DTE is almost always event-driven: earnings day, FDA decision day, a specific known catalyst. When you see large 0DTE flow on a single stock, look for the catalyst first. If there's no obvious event, treat it as a same-day momentum trade rather than informed positioning.

On earnings days especially, large 0DTE call or put sweeps on the underlying are often hedging against the post-close report rather than a directional bet on the stock itself. Distinguish between "buying calls because stock goes up" and "buying calls because IV will expand into the print even if stock goes sideways."

Using 0DTE flow as confirmation, not primary signal

The most reliable use of 0DTE flow is as a secondary confirmation layer, not a primary signal:

1. Identify a multi-day setup using 7–30 DTE flow showing sustained directional conviction.
2. Wait for 0DTE flow in the same direction on the same name, especially large premium sweeps at OTM strikes.
3. Use the convergence of multi-day conviction + same-day urgency as higher-confidence entry confirmation.
4. The 0DTE flow alone isn't enough, the alignment is the signal.

Treating 0DTE flow as a standalone signal leads to chasing momentum. Using it as confirmation within a broader flow framework adds a genuine edge, it tells you that whatever theme you've identified multi-day is actively being expressed today as well.

The SPY/QQQ 0DTE filter

For the indices specifically, 0DTE volume is so enormous that raw flow numbers are almost meaningless. A $10M SPY 0DTE sweep is unremarkable. Context is everything:

• Is the strike meaningfully OTM (more than 0.5% away from current price)? If not, it's likely hedging.
• Is the time of day early (before 10:30am) or mid-afternoon (after 2:00pm)? Both windows are more signal-rich than mid-day.
• Is the premium unusual vs the average for that time of day and strike distance? Scan for deviations from the baseline, not absolute size.
• Is it a put sweep when the market is up, or a call sweep when the market is down? Counter-trend 0DTE flow is more interesting than momentum-following flow.

0DTE market microstructure: bid-ask spreads, liquidity windows, and why size matters

The 0DTE options market has distinct microstructure characteristics that differ sharply from longer-dated options. Understanding these differences is not academic, they determine whether a given 0DTE print is even worth analyzing in the first place.

• Bid-ask spreads widen dramatically as the day progresses. The same gamma acceleration that makes 0DTE attractive for traders makes it expensive for market makers to hedge. As delta changes faster with each passing hour, dealers must continuously rebalance their books at an accelerating rate. They price that cost into wider spreads. A SPY 0DTE at-the-money contract that opened the day with a $0.01-$0.03 spread may carry a $0.08-$0.15 spread by 3:30 PM, even without a volatility spike.
• Institutional 0DTE participation is concentrated in SPY, QQQ, and SPX. These are the only 0DTE products with tight enough spreads for institutions to trade meaningful size efficiently. SPY at-the-money 0DTE typically prints $0.01-$0.03 wide in the morning session. That spread allows an institutional desk to put on $5M of premium at a round-trip cost that's acceptable. The same desk cannot replicate that efficiency in single-stock 0DTE, where spreads of $0.10-$0.50 on near-the-money contracts are standard, making the cost to enter and exit a large position prohibitive.
• Single-stock 0DTE is almost entirely retail. When you see 0DTE flow on AAPL, TSLA, or a mid-cap name, the bid-ask spread is the first filter. A contract priced at $0.40 mid with a $0.20 bid and $0.60 ask has a 50% round-trip cost relative to mid. No institutional desk sizes into that inefficiency at scale. The buyer is almost certainly retail, making the print noise regardless of the premium size.
• Use bid-ask spread as a hard filter. Any 0DTE signal in a contract where the bid-ask spread exceeds 15% of the mid-price should be filtered out by default. The economics of trading that contract eliminate institutional participation, and without institutional participation, 0DTE flow is speculative noise. This rule alone eliminates the majority of misleading single-stock 0DTE signals.
• The institutional liquidity windows are narrow. 0DTE institutional activity clusters in two windows: 9:30-11:00 AM (when opening-session hedges are established and overnight positioning is closed out) and 2:30-3:45 PM (when afternoon directional trades and end-of-day hedges are placed). The midday period, roughly 11:30 AM to 1:30 PM, is dominated by retail and low-conviction activity. During this window, even large premium prints are less reliable, institutions are not actively positioning in 0DTE during the lunch-hour drift.
• The final 15 minutes are purely mechanical. The 3:45-4:00 PM window produces no directional signal whatsoever. What occurs in those final minutes is expiration pinning (market makers defending strikes with massive open interest), delta-hedging forced by rapid gamma changes, and position liquidation by traders who do not want to hold into expiry. Volume can be enormous; informational content is zero. Treat any 0DTE print after 3:45 PM as noise by definition and do not interpret it directionally.

The practical implication: when screening 0DTE flow, sort by bid-ask spread first, time of day second, and premium size third. A $200K print in a contract with a tight spread during the opening hour is worth more analytical attention than a $2M print in a wide-spread contract during the lunch hour.

FOMC and macro event 0DTE: how scheduled catalysts change the flow interpretation

Federal Open Market Committee meeting days generate the most extreme 0DTE activity of any scheduled event in the options market. The dynamics on FOMC days require a completely separate interpretive framework, one where the standard 0DTE filters need to be partially suspended and replaced with event-specific logic.

• FOMC days produce the highest 0DTE volume of any scheduled event. More 0DTE notional trades on FOMC announcement days than on any other regular calendar item. The reason is structural: the Fed meeting creates a known, binary event with a specific announcement time (2:00 PM ET), which 0DTE options price perfectly. The implied move in SPX on FOMC days is frequently 0.8-1.5%, compared to an average daily move of 0.3-0.5%, and 0DTE options capture that elevated premium precisely.
• Pre-2:00 PM FOMC flow is anticipatory, not reactive. 0DTE activity before the 2:00 PM statement is directional positioning, traders who have a view on whether the Fed will surprise hawkishly or dovishly. This flow is often informed: participants who have carefully parsed prior Fed communications, regional Fed speeches, and economic data are making probability-weighted bets. Large OTM 0DTE prints before the announcement carry above-average informational content on FOMC days.
• The 2:00 PM volume spike is a repricing event, not a signal. The massive volume that occurs at the exact moment of the Fed announcement is not analyzable as a directional signal in real time. Both sides of the market are being hit simultaneously as the market reprices. What to watch instead: in the 5-10 minutes after the initial spike, which side is being accumulated? That post-announcement flow direction is the real-time market read on whether the statement was received as hawkish or dovish.
• The "FOMC straddle" pattern in flow data. Institutions that have high confidence in a large move but uncertain direction buy 0DTE straddles, both a call and a put at the same at-the-money strike. In flow data, this appears as simultaneous large call AND put accumulation at the same ATM strike, which can confuse directional analysis. When you see balanced, large-premium call and put buying at the same 0DTE strike before an event, the signal is not direction, it is confidence in magnitude. The market is pricing in a large move; the straddle buyer profits from either direction.
• Post-announcement flow during the press conference is the clearest real-time signal. Jerome Powell's press conference runs from roughly 2:30-3:30 PM. During this window, 0DTE positioning continues as traders react to his tone, not the statement text, but the improvised answers to questions. Large 0DTE call accumulation during a portion of the press conference suggests the market is reading that segment as dovish; large put accumulation reads as hawkish. This is the window where 0DTE flow on FOMC days provides the most actionable directional signal.
• CPI, PPI, payrolls, and GDP create similar but smaller 0DTE spikes. Major economic data releases at 8:30 AM ET create pre-release 0DTE positioning that mirrors the FOMC dynamic at a smaller scale. Note that the 8:30 AM 0DTE window is only available for SPX, SPX has 0DTE contracts available every trading day of the week, while SPY has 0DTE only on Monday, Wednesday, and Friday. Traders who want to use 0DTE options to position around Tuesday or Thursday 8:30 AM releases must use SPX contracts specifically.

The FOMC day framework applies equally to any event with a known time and binary outcome. The general rule: before the event, 0DTE flow is anticipatory and carries informational content; at the event, ignore the volume spike; after the event, track which side dominates in the 30-60 minute repricing window.

Dealer gamma positioning and the 0DTE flow feedback loop

The relationship between 0DTE options flow and dealer hedging creates a mechanical feedback loop that experienced traders exploit deliberately. Understanding this loop is essential for interpreting why 0DTE can cause price moves that seem disproportionate to the options activity that triggered them.

• Dealer gamma in 0DTE is at its mathematical maximum. For at-the-money options, gamma, the rate of change of delta with respect to the underlying price, reaches its peak value as expiration approaches. A 0DTE at-the-money option has dramatically higher gamma than a 30-DTE at-the-money option at the same strike. This means that when dealers sell 0DTE calls to buyers and hedge by buying the underlying, a small price increase requires them to buy significantly more stock than the same price increase would require with longer-dated options.
• The self-fulfilling gamma squeeze mechanism. If enough call buying pushes the underlying stock toward a call strike where dealers are short gamma, the dealers must buy the underlying to hedge. That buying pressure pushes the stock further up, which triggers more delta hedging, which creates more buying pressure. This cascade, where the options hedging itself drives the price move, is more powerful in 0DTE than any other expiry because gamma is amplified. Traders who understand gamma positioning try to identify the trigger point where this cascade might ignite and position ahead of it.
• Round-number strikes are gamma concentration points. Open interest in 0DTE options clusters heavily at round-number strikes (SPY at 450, 455, 460; SPX at 5000, 5050, 5100). If the underlying is within 0.5% of a strike with substantial 0DTE open interest, the gamma hedging activity at that strike creates a price magnet effect. The underlying is likely to pin near that strike, get rejected from it, or blow through it in an accelerating move, depending on whether dealers are short or long gamma at that level.
• Gamma effects are strongest in the final 2 hours. The gamma acceleration is a mathematical property of time remaining to expiry. At market open with 6.5 hours to go, gamma is elevated but manageable. In the final 2 hours, gamma for near-the-money strikes can be 3-5 times higher than at the open. This is why the 2:30-4:00 PM window sees the most dramatic gamma-driven price moves, a small directional shift near expiry can create outsized dealer hedging flows.
• Put gamma works identically in reverse. Concentrated put open interest at a strike creates selling pressure as price approaches from above. Dealers who are short puts must sell the underlying as the price falls toward the put strike, creating a downside gamma squeeze that mirrors the upside call squeeze. In practice, put gamma squeezes tend to be faster and more violent than call gamma squeezes because panic selling amplifies the mechanical hedging pressure.
• Using gamma exposure data as a context layer. Several data providers (including CBOE's own published data and third-party gamma modeling services) publish daily dealer gamma exposure by strike. When a significant 0DTE flow signal appears at a strike that also has high dealer gamma exposure, the combination is more actionable than either signal alone. The flow signal tells you someone is positioning; the gamma exposure tells you that the mechanics of dealer hedging will amplify any price move toward or away from that strike. These two data sources together form a more complete picture of 0DTE market structure than flow analysis alone.

The feedback loop summary: large 0DTE options buying at a specific strike forces dealer hedging, which moves the underlying toward that strike, which forces more hedging, which amplifies the move. This loop is why 0DTE activity at gamma-heavy strikes can produce price moves that appear disconnected from fundamental news, the options market is driving the equity market, not the reverse.

0DTE flow on non-index single stocks: when is individual equity 0DTE credible?

The blanket rule that single-stock 0DTE is noise is a useful starting point, but it is not universally true. There are specific conditions under which individual equity 0DTE flow carries genuine informational content that justifies further analysis.

• The liquidity threshold for credible single-stock 0DTE. For a single-stock 0DTE print to be worth analyzing, the underlying must have an options market averaging at least 50,000 contracts of daily volume, with bid-ask spreads on 0DTE near-the-money contracts no wider than $0.20. Below this threshold, the spread economics eliminate institutional participation entirely. Only a handful of names consistently clear this bar: AAPL, TSLA, NVDA, AMZN, META, and MSFT are the primary ones, with a secondary tier including GOOGL and a few large-cap financials.
• AAPL has the most credible single-stock 0DTE institutional signal. Apple is the most actively traded single-stock 0DTE name, with enough liquidity that institutional participation is occasionally visible in the flow patterns. AAPL 0DTE spreads in the morning session can be as tight as $0.05-$0.10 near the money, which is still 3-5 times wider than SPY but narrow enough for mid-sized institutional hedging. Large single-trade AAPL 0DTE prints above $300K premium in the first hour warrant attention.
• TSLA 0DTE is liquid but retail-dominated. Tesla has high 0DTE volume but the character of that volume is retail: scattered small prints throughout the day, frequent OTM strike activity, high cancellation and adjustment rates. The retail dominance makes TSLA 0DTE flow unreliable as an institutional signal even when premium appears large. NVDA, post-split, has seen meaningfully higher institutional participation in 0DTE relative to TSLA, making it the more credible signal when conditions are met.
• Distinguishing institutional from retail 0DTE in individual stocks. Institutional 0DTE prints in individual stocks have a distinct pattern: they are typically single large trades (not many small orders accumulated over time), they execute during specific time-of-day windows (first hour of trading, the 1:00-2:00 PM institutional window, or the final hour), they concentrate at round-number strikes rather than oddly specific ones, and they do not exhibit the repeated adjustment and cancellation behavior that characterizes retail directional betting.
• The earnings-day exception: ignore all single-stock 0DTE on earnings day. On the day of an earnings announcement, individual stock 0DTE volume explodes, and it is almost entirely retail speculation on the binary outcome. Earnings-day 0DTE provides zero informational signal about the actual earnings result. Every participant knows the catalyst exists; the 0DTE activity reflects the market-clearing price of that binary bet, not informed positioning. This rule is absolute: never use earnings-day single-stock 0DTE as a directional signal.
• The non-earnings credible 0DTE single-stock signal. The specific pattern that occasionally reflects genuine information-based positioning in individual equities is: large single-trade premium above $500K (not accumulated small orders), executed in the first hour of trading, at a specific directional strike rather than at-the-money (which would suggest hedging), with no obvious scheduled catalyst on that day. When all four conditions are met in a highly liquid name like AAPL or NVDA, the print warrants inclusion in a multi-factor analysis. It is still not sufficient as a standalone signal, but it is not noise either.

The key mental model: single-stock 0DTE credibility is a function of liquidity, spread, time-of-day, and the absence of a scheduled catalyst that would explain the activity as retail speculation. Run the checklist before including any individual equity 0DTE print in your analysis, most will be filtered out, but the ones that pass are worth tracking.

Risk management when trading on 0DTE-triggered signals

Using 0DTE flow as a signal to enter a longer-dated position introduces specific risk management requirements that differ from entering on multi-day accumulation signals. The speed and ephemerality of 0DTE activity means both the confirmation signals and the invalidation signals arrive faster than in traditional flow setups.

• Size smaller on initial entry when triggered by 0DTE. Because 0DTE activity can appear and reverse within the same session, a large call sweep at 10:00 AM can be followed by closing prints at 1:00 PM if the anticipated catalyst fails to materialize, the initial position size triggered by a 0DTE signal should be smaller than your standard entry. A reasonable starting point is 50-60% of normal size, with the intent to add confirmation in the following session if the thesis develops.
• Define the invalidation signal before entering. The invalidation of a 0DTE-triggered position is clear: if the underlying moves against the direction of the 0DTE flow signal within the same session, and the 0DTE activity does not confirm the reversal (no closing of the losing position, no opposite-direction accumulation), the original signal has failed. Do not wait for a multi-day drawdown to confirm what the same-day tape is already telling you, exit the longer-dated position promptly when the 0DTE signal invalidates.
• Set time stops, not just price stops. Positions entered on a 0DTE signal should have a defined maximum hold period of 3-5 trading sessions. The 0DTE activity signals that something is expected to happen today or very soon; if the anticipated catalyst has not materialized within that window, the informational edge behind the signal has decayed. Exit regardless of the profit or loss on the position. This discipline prevents a short-term momentum signal from becoming an indefinitely held lottery ticket.
• Apply the "0DTE as trigger, not thesis" principle consistently. The 0DTE flow identifies that a market participant believes something will happen today. Your analytical work is to determine whether there is a multi-day or multi-week fundamental or technical thesis that the same-day flow is previewing. If you cannot independently articulate why the underlying should move over the next 5-10 sessions, separate from the 0DTE activity itself, do not enter a multi-session position. The 0DTE flow is a timing catalyst, not a self-sufficient investment thesis.
• Tighter stops than standard options trades. Stop-loss levels for positions entered on 0DTE signals should be tighter than your standard options trade stops, for one specific reason: 0DTE signals have a higher false-positive rate than multi-day accumulation signals. A position that has been built over 5 sessions in the 30-DTE range represents sustained conviction that is harder to fake; a 0DTE print that appears in the first hour represents a single moment of activity that could be mechanical, hedging-related, or retail-driven despite passing the initial filters. The higher false-positive rate justifies smaller losses when wrong.
• Track the resolution of each 0DTE-triggered trade to build a personal dataset. Because 0DTE signals have lower base-rate reliability than multi-day signals, the fastest way to improve your framework is systematic outcome tracking. For each 0DTE signal you act on, record: the time of the signal, the specific conditions that made it pass your filter, the entry rationale, and the outcome. Over time, patterns emerge about which sub-categories of 0DTE signals are predictive in your specific trading universe and which are consistently noise.

The overarching risk management principle: treat 0DTE-triggered positions as higher-volatility, lower-probability entries that require correspondingly smaller initial sizes, faster invalidation responses, and mandatory time stops. The reward for getting 0DTE signal interpretation right is access to extremely timely entry points on developing multi-day moves, but only disciplined position management allows you to stay in that game across the inevitable false positives.

Case studies: three 0DTE flow sequences and how they translated into multi-day positions

Abstract frameworks become actionable through specific examples. The following three cases illustrate how 0DTE flow analysis works in practice, one successful call setup, one successful put setup, and one correctly rejected false positive.

Summary

0DTE options flow isn't useless, but it requires a filter that's far stricter than what you'd apply to multi-day flow. The dominant players in 0DTE are market makers, retail traders, and mechanical hedgers, not the sustained directional conviction that makes multi-week flow reliable.

When 0DTE flow is worth paying attention to: large premium at specific OTM strikes, early-session or mid-afternoon timing, counter-trend direction, and alignment with multi-day flow signals. When to filter it: low per-contract premium, mid-day window, momentum-chasing direction, and isolated single prints without repeat sweeps.

The traders who use 0DTE flow most effectively treat it as a real-time sentiment check on existing theses, not as the thesis itself. Use RadarPulse's DTE filter to separate same-day flow from multi-day flow, and watch for 0DTE confirmation that aligns with the institutional positioning you've already identified in the 7–30 DTE range.