0DTE Options Volume and Market Impact

0DTE options have gone from a niche product to the dominant force in the options market. Understanding the volume dynamics helps you trade with the flow, not against it.

The Volume Explosion

The numbers are staggering:

| Year | 0DTE % of SPX Options Volume | Daily 0DTE Contracts | 202018%~800,000 202125%~1,200,000 202237%~2,500,000 202344%~3,800,000 202448%~4,500,000 | 2025 | 50%+ | ~5,000,000+ |

Half of all SPX options volume now expires on the same day it's traded. This is a structural shift in how the market operates, not a temporary trend.

Who's Trading 0DTE?

The mix matters because different participants create different market dynamics:

Retail traders (~25% of volume): Primarily buying calls and puts for directional bets. Retail flow tends to be pro-cyclical — buying calls in rallies, buying puts in selloffs.

Market makers (~35%): Providing liquidity and hedging their exposure. Their hedging creates the gamma effects discussed in other guides.

Institutional/systematic traders (~30%): Using 0DTE for hedging, yield enhancement, and systematic strategies like daily iron condors.

Prop trading firms (~10%): High-frequency strategies that capture bid-ask spreads and short-term mispricings.

How 0DTE Volume Affects Intraday Prices

The Volatility Suppression Effect

On most days, the massive amount of 0DTE options sold (credit spreads, iron condors, covered calls) creates a volatility-suppressing effect:

  • Market makers collect net short gamma from institutional sellers
  • They hedge by buying dips and selling rallies
  • This creates a "wall" that keeps SPY in a tight range

    • Result: Average daily SPY range has compressed from 1.4% in 2020 to 0.9% in 2025 on days without major catalysts. The sheer volume of premium selling acts as a dampener.

    The Occasional Volatility Amplification

    When the market moves enough to blow through the concentrated 0DTE strikes, the effect reverses:

  • Short gamma positions force market makers to sell into declining prices
  • Stop losses on credit spreads trigger, adding selling pressure
  • The "walls" that contained price become accelerants

    • This explains the "calm-calm-CRASH" pattern in modern markets: most days are quiet, but when a move happens, it's fast and violent.

    End-of-Day Pinning

    The massive open interest at round-number strikes creates gravitational pull as expiration approaches. If SPY has 200,000 contracts of open interest at $545 and $550, the index tends to drift toward one of these levels in the final hour.

    This pinning effect is strongest between 3:00–3:45 PM and disappears in the final 15 minutes when gamma hedging unwinds.

    What This Means for Your Trading

    For Credit Spread Sellers

    The volatility suppression effect is your friend. Most days, the market stays range-bound, and your spreads expire worthless. But you need to respect the days when suppression breaks down:

  • Monitor total 0DTE open interest. When it's concentrated near current price, pinning is likely (good for sellers).
  • Watch for cascading stops. If price breaks through a high-OI strike, the move can accelerate beyond what normal analysis would suggest.

    • For Directional Buyers

    You're fighting against volatility suppression most days. This means:

  • Be selective. Only take directional trades when a catalyst exists (earnings, economic data, FOMC).
  • Aim for moves beyond the high-OI strikes. If $545 and $550 are the big OI levels, your call target should be above $550 — the breakout through concentrated OI is where the acceleration happens.

    • For All Traders

    Volume patterns throughout the day:

    | Time Window | Typical Volume | Implication | 9:30–10:00 AMVery highInstitutions setting positions 10:00 AM–12:00 PMHighActive trading, good fills 12:00–2:00 PMLowWide spreads, avoid new entries 2:00–3:00 PMIncreasingAfternoon flow picks up | 3:00–4:00 PM | Very high | Expiration hedging, gamma pinning |

    The Structural Concern

    Some market participants worry that 0DTE volume has made the market fragile — stable most of the time but prone to sudden, sharp moves when the gamma dam breaks. The data partially supports this view: the frequency of 2%+ intraday moves has increased since 2022, even as average daily volatility has decreased.

    For individual traders, the practical implication is clear: position sizing discipline matters more than ever. The occasional sharp move will happen, and when it does, it'll be faster than historical norms suggest. Keep your per-trade risk at 1–2% and you'll weather these events. Backtest your strategy across multiple market regimes in OptionsPilot to see exactly how your positions would handle these tail events.