Here is a number worth sitting with. In February 2026, same-day-expiry options — 0DTE — made up roughly 63% of all SPX options volume, a record. Not a fringe corner of the market. The majority.

Stop and feel the weight of that. More than half of the trading in the most important equity index on earth is now in contracts that are born and die inside a single session. A decade ago this product barely existed. Today it is the market.

If you trade SPX, SPY, or anything that moves with them, you are not trading the same instrument your mentor learned on. You’re trading inside a structure that behaves differently — and most retail traders have no idea the floor moved under them.

What same-day expiry actually does

An option’s influence on the underlying isn’t constant. It’s concentrated by gamma — the rate at which a dealer’s hedging requirement changes as price moves. The closer an option gets to expiry and to its strike, the more violently that hedging requirement swings. A 0DTE option is all gamma, right now, packed into a few hours.

So when the whole market crowds into same-day strikes, you get an enormous, twitchy hedging load sitting on top of price for the entire session. Dealers who are short those options have to buy and sell the underlying continuously just to stay flat. That mechanical flow doesn’t care about your thesis. It doesn’t read the headlines. It just hedges.

The old mental model price reflects what traders think things are worth The 2026 reality intraday price is heavily shaped by dealers hedging same-day gamma

This is the part that costs people money: you think you’re trading the news, and a lot of the time you’re trading the hedge. The market chops sideways in a tight range and you invent a fundamental story for it — when the real explanation is that dealers are long gamma and mechanically fading every push. Or it rips through a level on no news at all, and you call it “momentum” — when dealers flipped short gamma and are now chasing the move, pouring fuel on it.

What it means for how you trade

You don’t need a terminal to act on this. You need to respect three things.

One: the character of the day is often set before the news. Whether price is going to grind-and-pin or trend-and-extend has a lot to do with positioning, not the catalyst. Read the regime first; trade the catalyst second.

Two: the dead zone is real. Same-day gamma is heaviest at the open and into the close, and thinnest in the middle of the day. The midday chop where you keep getting stopped out in both directions isn’t bad luck — it’s low participation against a pinning hedge. Often the correct trade there is no trade.

Three — and this is the one that quietly bleeds accounts: buying 0DTE options taxes you twice. You’re fighting time decay that accelerates by the hour, and you’re paying a volatility premium that, on average, is too rich. You can be right on direction and still lose, because the move didn’t come fast enough or big enough to clear what you paid. The market loves a retail trader who buys cheap same-day calls. It’s the most reliable customer it has.

The trap, plainly The danger isn't that 0DTE exists. It's trading it as if you're reacting to fundamentals when you're actually swimming inside a dealer hedging machine — and never knowing the difference.

The read we keep for ourselves

Knowing that gamma shapes the session is free. Knowing which regime you’re in right now — long-gamma pin or short-gamma trend — is the part that matters, and the part we measure. We’ll teach you what each regime looks like and how it changes the playbook. We won’t hand you the thresholds our engine uses to call it. That line is where the education ends and ChopSniper begins.

For now, take the one idea that’s worth more than any signal: on most days, the biggest force in the room isn’t the news. It’s the hedge. Once you can feel that, you stop fighting the machine — and you start reading through the chop.