0DTE Options Trading: The Operator's Guide

Zero-days-to-expiration (0DTE) options have gone from niche to dominant. On any given Friday, more than half of SPX options volume trades in contracts that expire that afternoon. The mechanics of these instruments are nothing like the 30-DTE textbook — gamma, theta, and dealer hedging dominate, and the trader who doesn't understand them ends up paying the trader who does.

Why 0DTE is structurally different

Two things go to infinity as expiration approaches:

• Gamma — for options near the money. A 0DTE ATM call can go from 0.50 delta to 0.95 delta in a single point of underlying movement.
• Theta — the time value of any OTM option collapses to zero by 4PM ET. Hold a 0DTE call that's 5 points out of the money at 3PM and it's almost certainly going to zero.

These dynamics create two regimes: the "gamma melt" where directional moves accelerate violently, and the "pin" where price gets magnetically stuck to a strike with massive open interest.

The dealer-hedging connection

Market makers can't avoid 0DTE risk because they're the counterparty to everyone else. When dealers are net long 0DTE calls (typical in positive-gamma regimes), they sell stock into rallies and buy into dips to stay delta-flat — which actively suppresses volatility and creates pinning behavior. When dealers are short 0DTE (negative gamma), the opposite happens: they amplify every move.

OptionsDeck's GEX dashboard tells you in real time which regime you're in. Trading 0DTE without checking GEX is like driving with your eyes closed.

Structures that work

1. Bull put credit spread in positive gamma + strong support — collect premium, theta works fast, gamma pin keeps you safe.
2. Bear call credit spread under a call wall — same logic on the other side.
3. Iron butterfly at predicted pin strike — when GEX shows massive call+put OI clustering at one strike, the pin is real.
4. Long call/put 30 minutes before a Powell presser or FOMC — vol crush works against you, but a 3% move pays everything.

Structures that don't work

1. Naked long 0DTE OTM calls "for the lotto" — 95%+ go to zero. Negative expectancy.
2. Iron condors with too-tight wings — gamma in the last hour can blow through both wings.
3. Selling naked 0DTE puts under a put wall in negative gamma — when the wall breaks, you take max loss in minutes.

Reading flow on 0DTE

The unusual options flow signal is even more important on 0DTE because the prints are mostly real positioning intent (very little is closing). Aggressive buyer-initiated 0DTE call buying on SPY before a Fed pause hint is what professional tape readers actually pay attention to.

Try it

OptionsDeck streams 0DTE options trades from the OPRA-direct WebSocket within ~100ms of execution. The AI Strategist factors gamma regime and IV into every 0DTE idea. Open the trial and watch the SPY flow scanner for one cash session — you'll never trade 0DTE the same way.